From 41dff40252895825c54c007e88afb33350069b37 Mon Sep 17 00:00:00 2001
From: Henrique Holanda <contato@henriqueholanda.com.br>
Date: Thu, 4 Oct 2018 10:02:44 -0300
Subject: [PATCH] Updating to PHP7 (#44)

On this change, I'm doing some improvements to it works with new features of PHP (properties types, return types)
---
 README.md                                     |  4 +-
 src/AbstractDocument.php                      | 39 +++++++++------
 src/Cnh.php                                   | 12 ++---
 src/Cnpj.php                                  |  8 +--
 src/Cns.php                                   |  8 +--
 src/Cns/CnsCalculator.php                     |  2 +-
 src/Cns/TemporaryCalculator.php               |  2 +-
 src/Cpf.php                                   |  8 +--
 src/DigitCalculable.php                       |  2 +-
 src/DigitCalculator.php                       | 30 ++++++------
 src/Formattable.php                           |  2 +-
 src/JudiciaryProcess.php                      | 14 +++---
 src/PisPasep.php                              |  8 +--
 src/Renavam.php                               | 10 ++--
 src/Sped/AbstractAccessKey.php                | 26 +++++-----
 src/Sped/CTe.php                              | 12 ++---
 src/Sped/CTeOther.php                         | 12 ++---
 src/Sped/EmissionType.php                     | 22 ++++-----
 src/Sped/MDFe.php                             | 12 ++---
 src/Sped/Model.php                            | 20 ++++----
 src/Sped/NFCe.php                             | 12 ++---
 src/Sped/NFe.php                              | 12 ++---
 src/StateRegistration.php                     | 14 +++---
 src/StateRegistration/Acre.php                |  2 +-
 src/StateRegistration/Alagoas.php             |  2 +-
 src/StateRegistration/Amapa.php               | 12 ++---
 src/StateRegistration/Amazonas.php            |  2 +-
 src/StateRegistration/Bahia.php               |  4 +-
 src/StateRegistration/Ceara.php               |  2 +-
 src/StateRegistration/DistritoFederal.php     |  2 +-
 src/StateRegistration/EspiritoSanto.php       |  2 +-
 src/StateRegistration/Goias.php               | 12 ++---
 src/StateRegistration/Maranhao.php            |  2 +-
 src/StateRegistration/MatoGrosso.php          |  4 +-
 src/StateRegistration/MatoGrossoSul.php       |  2 +-
 src/StateRegistration/MinasGerais.php         |  2 +-
 src/StateRegistration/Para.php                |  2 +-
 src/StateRegistration/Paraiba.php             |  2 +-
 src/StateRegistration/Parana.php              |  2 +-
 src/StateRegistration/Pernambuco.php          | 20 ++++----
 src/StateRegistration/Pernambuco/EFisco.php   |  2 +-
 src/StateRegistration/Pernambuco/Old.php      |  2 +-
 src/StateRegistration/Piaui.php               |  2 +-
 src/StateRegistration/RioDeJaneiro.php        |  2 +-
 src/StateRegistration/RioGrandeDoNorte.php    | 12 ++---
 src/StateRegistration/RioGrandeDoSul.php      |  2 +-
 src/StateRegistration/Rondonia.php            |  2 +-
 src/StateRegistration/Roraima.php             |  2 +-
 src/StateRegistration/SantaCatarina.php       |  2 +-
 src/StateRegistration/SaoPaulo.php            | 20 ++++----
 src/StateRegistration/SaoPaulo/Rural.php      |  8 +--
 src/StateRegistration/SaoPaulo/Urban.php      | 10 ++--
 src/StateRegistration/Sergipe.php             |  2 +-
 src/StateRegistration/State.php               | 18 +++----
 src/StateRegistration/StateInterface.php      | 16 +++---
 src/StateRegistration/Tocantins.php           | 20 ++++----
 src/StateRegistration/Tocantins/Eleven.php    |  6 +--
 src/StateRegistration/Tocantins/Nine.php      |  2 +-
 src/Voter.php                                 | 16 +++---
 tests/CnhTest.php                             | 13 ++---
 tests/CnpjTest.php                            | 13 ++---
 tests/CnsTest.php                             | 13 ++---
 tests/CpfTest.php                             | 13 ++---
 tests/DigitCalculatorTest.php                 |  2 +-
 tests/DocumentTestCase.php                    | 49 +++++--------------
 tests/JudiciaryProcessTest.php                | 13 ++---
 tests/PisPasepTest.php                        | 13 ++---
 tests/RenavamTest.php                         | 13 ++---
 tests/Sped/CTeOtherTest.php                   | 15 +++---
 tests/Sped/CTeTest.php                        | 15 +++---
 tests/Sped/MDFeTest.php                       | 15 +++---
 tests/Sped/NFCeTest.php                       | 15 +++---
 tests/Sped/NFeTest.php                        | 15 +++---
 tests/StateRegistration/AcreTest.php          | 13 ++---
 tests/StateRegistration/AlagoasTest.php       | 13 ++---
 tests/StateRegistration/AmapaTest.php         | 13 ++---
 tests/StateRegistration/AmazonasTest.php      | 13 ++---
 tests/StateRegistration/BahiaTest.php         | 13 ++---
 tests/StateRegistration/CearaTest.php         | 13 ++---
 .../StateRegistration/DistritoFederalTest.php | 13 ++---
 tests/StateRegistration/EspiritoSantoTest.php | 13 ++---
 tests/StateRegistration/GoiasTest.php         | 13 ++---
 tests/StateRegistration/MaranhaoTest.php      | 13 ++---
 tests/StateRegistration/MatoGrossoSulTest.php | 13 ++---
 tests/StateRegistration/MatoGrossoTest.php    | 13 ++---
 tests/StateRegistration/MinasGeraisTest.php   | 13 ++---
 tests/StateRegistration/ParaTest.php          | 13 ++---
 tests/StateRegistration/ParaibaTest.php       | 13 ++---
 tests/StateRegistration/ParanaTest.php        | 13 ++---
 tests/StateRegistration/PernambucoTest.php    | 13 ++---
 tests/StateRegistration/PiauiTest.php         | 13 ++---
 tests/StateRegistration/RioDeJaneiroTest.php  | 13 ++---
 .../RioGrandeDoNorteTest.php                  | 13 ++---
 .../StateRegistration/RioGrandeDoSulTest.php  | 13 ++---
 tests/StateRegistration/RondoniaTest.php      | 13 ++---
 tests/StateRegistration/RoraimaTest.php       | 13 ++---
 tests/StateRegistration/SantaCatarinaTest.php | 13 ++---
 tests/StateRegistration/SaoPauloTest.php      | 13 ++---
 tests/StateRegistration/SergipeTest.php       | 13 ++---
 tests/StateRegistration/TocantinsTest.php     | 13 ++---
 tests/VoterTest.php                           | 13 ++---
 101 files changed, 559 insertions(+), 535 deletions(-)

diff --git a/README.md b/README.md
index 0fd1648..412f321 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ Install the library using [composer][1]. Add the following to your `composer.jso
 ```json
 {
     "require": {
-        "brazanation/documents": "1.0.*"
+        "brazanation/documents": "2.0.*"
     }
 }
 ```
@@ -31,7 +31,7 @@ $ composer.phar install
 or
 
 ```sh
-$ composer require brazanation/documents 1.0.*
+$ composer require brazanation/documents 2.0.*
 ```
 
 ### CPF (cadastro de pessoas físicas)
diff --git a/src/AbstractDocument.php b/src/AbstractDocument.php
index 54dffd8..e4d7dd6 100644
--- a/src/AbstractDocument.php
+++ b/src/AbstractDocument.php
@@ -48,22 +48,26 @@ abstract class AbstractDocument implements DigitCalculable, Formattable
      * @param int $numberOfDigits Max length of checker digits.
      * @param string $type Document name/type.
      */
-    public function __construct($number, $length, $numberOfDigits, $type)
-    {
-        $this->type = (string) $type;
-        $this->numberOfDigits = (int) $numberOfDigits;
-        $this->length = (int) $length;
+    public function __construct(
+        string $number,
+        int $length,
+        int $numberOfDigits,
+        string $type
+    ) {
+        $this->type = $type;
+        $this->numberOfDigits = $numberOfDigits;
+        $this->length = $length;
         $this->digit = $this->extractCheckerDigit($number);
         $this->assert($number);
         $this->number = $number;
     }
 
-    public function __get($name)
+    public function __get(string $name)
     {
         return $this->$name;
     }
 
-    public function __set($name, $value)
+    public function __set(string $name, string $value)
     {
         throw Exception\Readonly::notAllowed(static::class, $name);
     }
@@ -75,7 +79,7 @@ public function __set($name, $value)
      *
      * @return AbstractDocument|boolean Returns a new Document instance or FALSE on failure.
      */
-    abstract public static function createFromString($number);
+    abstract public static function createFromString(string $number);
 
     /**
      * Try to create a Document object from given number.
@@ -87,8 +91,13 @@ abstract public static function createFromString($number);
      *
      * @return AbstractDocument|boolean Returns a new Document instance or FALSE on failure.
      */
-    protected static function tryCreateFromString($class, $number, $length, $numberOfDigits, $type)
-    {
+    protected static function tryCreateFromString(
+        string $class,
+        string $number,
+        int $length,
+        int $numberOfDigits,
+        string $type
+    ) {
         try {
             return new $class($number, $length, $numberOfDigits, $type);
         } catch (Exception\InvalidDocument $exception) {
@@ -101,7 +110,7 @@ protected static function tryCreateFromString($class, $number, $length, $numberO
      *
      * @return string
      */
-    public function __toString()
+    public function __toString() : string
     {
         return "{$this->number}";
     }
@@ -114,7 +123,7 @@ public function __toString()
      * @throws Exception\InvalidDocument when number is empty
      * @throws Exception\InvalidDocument when number is not valid
      */
-    protected function assert($number)
+    protected function assert(string $number)
     {
         if (empty($number)) {
             throw Exception\InvalidDocument::notEmpty($this->type);
@@ -131,7 +140,7 @@ protected function assert($number)
      *
      * @return bool Returns true if it is a valid number, otherwise false.
      */
-    protected function isValid($number)
+    protected function isValid(string $number) : bool
     {
         $baseNumber = $this->extractBaseNumber($number);
 
@@ -157,7 +166,7 @@ protected function isValid($number)
      *
      * @return string Returns only base number without checker digit.
      */
-    protected function extractBaseNumber($number)
+    protected function extractBaseNumber(string $number) : string
     {
         return substr($number, 0, -($this->numberOfDigits));
     }
@@ -169,7 +178,7 @@ protected function extractBaseNumber($number)
      *
      * @return string Returns only checker digit.
      */
-    protected function extractCheckerDigit($number)
+    protected function extractCheckerDigit(string $number) : string
     {
         return substr($number, -($this->numberOfDigits));
     }
diff --git a/src/Cnh.php b/src/Cnh.php
index e88d9ae..4afe794 100644
--- a/src/Cnh.php
+++ b/src/Cnh.php
@@ -17,13 +17,13 @@ final class Cnh extends AbstractDocument
      *
      * @param string $cnh Only accept numbers
      */
-    public function __construct($cnh)
+    public function __construct(string $cnh)
     {
         $cnh = preg_replace('/\D/', '', $cnh);
         parent::__construct($cnh, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
 
-    public static function createFromString($number)
+    public static function createFromString(string $number)
     {
         return parent::tryCreateFromString(self::class, $number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
@@ -31,7 +31,7 @@ public static function createFromString($number)
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $firstDigit = $this->calculateFirstDigit($baseNumber);
         $secondDigit = $this->calculateSecondDigit($baseNumber);
@@ -42,7 +42,7 @@ public function calculateDigit($baseNumber)
     /**
      * {@inheritdoc}
      */
-    public function format()
+    public function format() : string
     {
         return "{$this}";
     }
@@ -54,7 +54,7 @@ public function format()
      *
      * @return string Returns a calculated checker digit.
      */
-    private function calculateFirstDigit($baseNumber)
+    private function calculateFirstDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->withMultipliersInterval(1, 9);
@@ -72,7 +72,7 @@ private function calculateFirstDigit($baseNumber)
      *
      * @return string Returns a calculated checker digit.
      */
-    private function calculateSecondDigit($baseNumber)
+    private function calculateSecondDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->withMultipliers([9, 8, 7, 6, 5, 4, 3, 2, 1]);
diff --git a/src/Cnpj.php b/src/Cnpj.php
index 7829c49..bb3964c 100644
--- a/src/Cnpj.php
+++ b/src/Cnpj.php
@@ -17,13 +17,13 @@ final class Cnpj extends AbstractDocument
      *
      * @param string $cnpj Only accept numbers
      */
-    public function __construct($cnpj)
+    public function __construct(string $cnpj)
     {
         $cnpj = preg_replace('/\D/', '', $cnpj);
         parent::__construct($cnpj, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
 
-    public static function createFromString($number)
+    public static function createFromString(string $number)
     {
         return parent::tryCreateFromString(self::class, $number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
@@ -31,7 +31,7 @@ public static function createFromString($number)
     /**
      * {@inheritdoc}
      */
-    public function format()
+    public function format() : string
     {
         return preg_replace(self::REGEX, '$1.$2.$3/$4-$5', "{$this}");
     }
@@ -39,7 +39,7 @@ public function format()
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/Cns.php b/src/Cns.php
index b1df3b4..97c91c6 100644
--- a/src/Cns.php
+++ b/src/Cns.php
@@ -22,13 +22,13 @@ final class Cns extends AbstractDocument
      *
      * @param string $number
      */
-    public function __construct($number)
+    public function __construct(string $number)
     {
         $number = preg_replace('/\D/', '', $number);
         parent::__construct($number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
 
-    public static function createFromString($number)
+    public static function createFromString(string $number)
     {
         return parent::tryCreateFromString(self::class, $number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
@@ -36,7 +36,7 @@ public static function createFromString($number)
     /**
      * {@inheritdoc}
      */
-    public function format()
+    public function format() : string
     {
         return preg_replace(self::REGEX, self::FORMAT, "{$this}");
     }
@@ -49,7 +49,7 @@ public function format()
      * For numbers starting with 7, 8 or 9 will use TemporaryCalculator,
      * otherwise CnsCalculator.
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new CnsCalculator();
 
diff --git a/src/Cns/CnsCalculator.php b/src/Cns/CnsCalculator.php
index 0d07103..88b32f0 100644
--- a/src/Cns/CnsCalculator.php
+++ b/src/Cns/CnsCalculator.php
@@ -10,7 +10,7 @@ final class CnsCalculator implements DigitCalculable
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $pis = substr($baseNumber, 0, 11);
 
diff --git a/src/Cns/TemporaryCalculator.php b/src/Cns/TemporaryCalculator.php
index ff34076..92fe61c 100644
--- a/src/Cns/TemporaryCalculator.php
+++ b/src/Cns/TemporaryCalculator.php
@@ -10,7 +10,7 @@ class TemporaryCalculator implements DigitCalculable
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->withMultipliersInterval(1, 15);
diff --git a/src/Cpf.php b/src/Cpf.php
index fa34b43..6b597f8 100644
--- a/src/Cpf.php
+++ b/src/Cpf.php
@@ -17,13 +17,13 @@ final class Cpf extends AbstractDocument
      *
      * @param string $number Only accept numbers
      */
-    public function __construct($number)
+    public function __construct(string $number)
     {
         $number = preg_replace('/\D/', '', $number);
         parent::__construct($number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
 
-    public static function createFromString($number)
+    public static function createFromString(string $number)
     {
         return parent::tryCreateFromString(self::class, $number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
@@ -31,7 +31,7 @@ public static function createFromString($number)
     /**
      * @return string Returns formatted number, such as: 000.000.000-00
      */
-    public function format()
+    public function format() : string
     {
         return preg_replace(self::REGEX, '$1.$2.$3-$4', "{$this}");
     }
@@ -39,7 +39,7 @@ public function format()
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->withMultipliersInterval(2, 11);
diff --git a/src/DigitCalculable.php b/src/DigitCalculable.php
index 0d4244d..11f3eec 100644
--- a/src/DigitCalculable.php
+++ b/src/DigitCalculable.php
@@ -11,5 +11,5 @@ interface DigitCalculable
      *
      * @return string Returns the checker digit.
      */
-    public function calculateDigit($baseNumber);
+    public function calculateDigit(string $baseNumber) : string;
 }
diff --git a/src/DigitCalculator.php b/src/DigitCalculator.php
index 8fffeca..f0d09b9 100644
--- a/src/DigitCalculator.php
+++ b/src/DigitCalculator.php
@@ -82,7 +82,7 @@ class DigitCalculator
      *
      * @param string $number Base numeric section to be calculate your digit.
      */
-    public function __construct($number)
+    public function __construct(string $number)
     {
         $this->number = new \ArrayObject(str_split(strrev($number)));
         $this->multipliers = new \ArrayObject();
@@ -107,7 +107,7 @@ public function __construct($number)
      *
      * @return DigitCalculator
      */
-    public function withMultipliersInterval($start, $end)
+    public function withMultipliersInterval(int $start, int $end) : DigitCalculator
     {
         $multipliers = [];
         for ($i = $start; $i <= $end; ++$i) {
@@ -127,7 +127,7 @@ public function withMultipliersInterval($start, $end)
      *
      * @return DigitCalculator
      */
-    public function withMultipliers(array $multipliers)
+    public function withMultipliers(array $multipliers) : DigitCalculator
     {
         $multipliers = array_map(function ($multiplier) {
             if (!assert(is_int($multiplier))) {
@@ -149,7 +149,7 @@ public function withMultipliers(array $multipliers)
      *
      * @return DigitCalculator
      */
-    public function useComplementaryInsteadOfModule()
+    public function useComplementaryInsteadOfModule() : DigitCalculator
     {
         $this->additional = true;
 
@@ -166,7 +166,7 @@ public function useComplementaryInsteadOfModule()
      *
      * @return DigitCalculator
      */
-    public function replaceWhen($replaceTo, ...$integers)
+    public function replaceWhen(string $replaceTo, ...$integers) : DigitCalculator
     {
         foreach ($integers as $integer) {
             $this->replacements->offsetSet($integer, $replaceTo);
@@ -184,7 +184,7 @@ public function replaceWhen($replaceTo, ...$integers)
      *
      * @return DigitCalculator
      */
-    public function withModule($module)
+    public function withModule(int $module) : DigitCalculator
     {
         $this->module = $module;
 
@@ -199,7 +199,7 @@ public function withModule($module)
      *
      * @return DigitCalculator
      */
-    public function singleSum()
+    public function singleSum() : DigitCalculator
     {
         $this->singleSum = true;
 
@@ -211,7 +211,7 @@ public function singleSum()
      *
      * @return string Returns a single calculated digit.
      */
-    public function calculate()
+    public function calculate() : string
     {
         $sum = 0;
         $position = 0;
@@ -238,7 +238,7 @@ public function calculate()
      *
      * @return string Returns digit replaced if it has been mapped, otherwise returns given digit.
      */
-    private function replaceDigit($digit)
+    private function replaceDigit(string $digit) : string
     {
         if ($this->replacements->offsetExists($digit)) {
             return $this->replacements->offsetGet($digit);
@@ -254,7 +254,7 @@ private function replaceDigit($digit)
      *
      * @return int Returns calculated digit.
      */
-    private function calculateAdditionalDigit($digit)
+    private function calculateAdditionalDigit(string $digit) : int
     {
         if ($this->additional) {
             $digit = $this->module - $digit;
@@ -270,7 +270,7 @@ private function calculateAdditionalDigit($digit)
      *
      * @return int Returns a calculated total.
      */
-    private function calculateSingleSum($total)
+    private function calculateSingleSum(int $total) : int
     {
         if ($this->singleSum) {
             return intval(($total / 10) + ($total % 10));
@@ -286,7 +286,7 @@ private function calculateSingleSum($total)
      *
      * @return int Returns next position or zero (0) when it is greater than number of defined multipliers.
      */
-    private function nextMultiplier($position)
+    private function nextMultiplier(int $position) : int
     {
         ++$position;
         if ($position == $this->multipliers->count()) {
@@ -303,7 +303,7 @@ private function nextMultiplier($position)
      *
      * @return DigitCalculator
      */
-    public function addDigit($digit)
+    public function addDigit(string $digit) : DigitCalculator
     {
         $numbers = $this->number->getArrayCopy();
         array_unshift($numbers, $digit);
@@ -319,7 +319,7 @@ public function addDigit($digit)
      *
      * @return DigitCalculator
      */
-    public function multiplySumBy($multiplier)
+    public function multiplySumBy(int $multiplier) : DigitCalculator
     {
         $this->sumMultiplier = $multiplier;
 
@@ -333,7 +333,7 @@ public function multiplySumBy($multiplier)
      *
      * @return int
      */
-    private function calculateSumMultiplier($sum)
+    private function calculateSumMultiplier(int $sum) : int
     {
         return $this->sumMultiplier * $sum;
     }
diff --git a/src/Formattable.php b/src/Formattable.php
index c5a63bd..3fe55b3 100644
--- a/src/Formattable.php
+++ b/src/Formattable.php
@@ -9,5 +9,5 @@ interface Formattable
      *
      * @return string Returns formatted number.
      */
-    public function format();
+    public function format() : string ;
 }
diff --git a/src/JudiciaryProcess.php b/src/JudiciaryProcess.php
index ef928b2..d25aed7 100644
--- a/src/JudiciaryProcess.php
+++ b/src/JudiciaryProcess.php
@@ -59,14 +59,14 @@ final class JudiciaryProcess extends AbstractDocument
      */
     private $origin;
 
-    public function __construct($number)
+    public function __construct(string $number)
     {
         $number = preg_replace('/\D/', '', $number);
         $this->extractNumbers($number);
         parent::__construct($number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
 
-    public static function createFromString($number)
+    public static function createFromString(string $number)
     {
         return parent::tryCreateFromString(self::class, $number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
@@ -76,7 +76,7 @@ public static function createFromString($number)
      *
      * @param string $number
      */
-    private function extractNumbers($number)
+    private function extractNumbers(string $number)
     {
         $number = str_pad($number, self::LENGTH, '0', STR_PAD_RIGHT);
 
@@ -88,19 +88,19 @@ private function extractNumbers($number)
         $this->origin = $matches[6];
     }
 
-    public function format()
+    public function format() : string
     {
         $number = str_pad($this->number, self::LENGTH, '0', STR_PAD_RIGHT);
 
         return preg_replace(self::REGEX, '$1-$2.$3.$4.$5.$6', "{$number}");
     }
 
-    protected function extractCheckerDigit($number)
+    protected function extractCheckerDigit(string $number) : string
     {
         return substr($number, 7, 2);
     }
 
-    protected function extractBaseNumber($number)
+    protected function extractBaseNumber(string $number) : string
     {
         return "{$this->sequentialNumber}{$this->year}{$this->judiciary}{$this->court}{$this->origin}";
     }
@@ -116,7 +116,7 @@ protected function extractBaseNumber($number)
      *
      * @return string
      */
-    public function calculateDigit($input)
+    public function calculateDigit(string $input) : string
     {
         $remainderNumber = intval($this->sequentialNumber) % 97;
 
diff --git a/src/PisPasep.php b/src/PisPasep.php
index e173118..d17d6b1 100644
--- a/src/PisPasep.php
+++ b/src/PisPasep.php
@@ -17,13 +17,13 @@ final class PisPasep extends AbstractDocument
      *
      * @param $number
      */
-    public function __construct($number)
+    public function __construct(string $number)
     {
         $number = preg_replace('/\D/', '', $number);
         parent::__construct($number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
 
-    public static function createFromString($number)
+    public static function createFromString(string $number)
     {
         return parent::tryCreateFromString(self::class, $number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
@@ -31,7 +31,7 @@ public static function createFromString($number)
     /**
      * @return string Returns formatted number, such as: 00.00000.00-0
      */
-    public function format()
+    public function format() : string
     {
         return preg_replace(self::REGEX, '$1.$2.$3-$4', "{$this}");
     }
@@ -39,7 +39,7 @@ public function format()
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->withMultipliersInterval(2, 9);
diff --git a/src/Renavam.php b/src/Renavam.php
index fe4d6c3..126935d 100644
--- a/src/Renavam.php
+++ b/src/Renavam.php
@@ -17,14 +17,14 @@ final class Renavam extends AbstractDocument
      *
      * @param string $renavam Only accept numbers
      */
-    public function __construct($renavam)
+    public function __construct(string $renavam)
     {
         $renavam = preg_replace('/\D/', '', $renavam);
         $renavam = $this->padNumber($renavam);
         parent::__construct($renavam, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
 
-    public static function createFromString($number)
+    public static function createFromString(string $number)
     {
         return parent::tryCreateFromString(self::class, $number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
@@ -36,7 +36,7 @@ public static function createFromString($number)
      *
      * @return string
      */
-    private function padNumber($number)
+    private function padNumber(string $number) : string
     {
         if (empty($number)) {
             return '';
@@ -48,7 +48,7 @@ private function padNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function format()
+    public function format() : string
     {
         return preg_replace(self::REGEX, '$1.$2-$3', "{$this}");
     }
@@ -56,7 +56,7 @@ public function format()
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         //$calculator->withMultipliers([3, 2, 9, 8, 7, 6, 5, 4, 3, 2]);
diff --git a/src/Sped/AbstractAccessKey.php b/src/Sped/AbstractAccessKey.php
index cb21d5f..4865982 100644
--- a/src/Sped/AbstractAccessKey.php
+++ b/src/Sped/AbstractAccessKey.php
@@ -78,7 +78,7 @@ abstract class AbstractAccessKey extends AbstractDocument
      *
      * @param $accessKey
      */
-    public function __construct($accessKey)
+    public function __construct(string $accessKey)
     {
         $accessKey = preg_replace('/\D/', '', $accessKey);
         parent::__construct($accessKey, static::LENGTH, static::NUMBER_OF_DIGITS, static::LABEL);
@@ -86,7 +86,7 @@ public function __construct($accessKey)
         $this->loadFromKey($accessKey);
     }
 
-    public static function createFromString($number)
+    public static function createFromString(string $number)
     {
         return parent::tryCreateFromString(static::class, $number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
@@ -94,9 +94,9 @@ public static function createFromString($number)
     /**
      * @return Model
      */
-    abstract protected function defaultModel();
+    abstract protected function defaultModel() : Model;
 
-    protected function validateModel($accessKey)
+    protected function validateModel(string $accessKey)
     {
         $model = new Model(substr($accessKey, 20, 2));
         if (!$this->defaultModel()->equalsTo($model)) {
@@ -104,7 +104,7 @@ protected function validateModel($accessKey)
         }
     }
 
-    private function loadFromKey($accessKey)
+    private function loadFromKey(string $accessKey)
     {
         $startPosition = 0;
         $this->state = substr($accessKey, $startPosition, 2);
@@ -149,15 +149,15 @@ private function loadFromKey($accessKey)
      * @return AbstractAccessKey
      */
     protected static function generateKey(
-        $state,
+        int $state,
         \DateTime $generatedAt,
         Cnpj $cnpj,
         Model $model,
-        $sequence,
-        $invoiceNumber,
+        int $sequence,
+        int $invoiceNumber,
         EmissionType $emissionType,
-        $controlNumber
-    ) {
+        int $controlNumber
+    ) : AbstractAccessKey {
         $yearMonth = $generatedAt->format('ym');
         $sequence = str_pad($sequence, 3, 0, STR_PAD_LEFT);
         $invoiceNumber = str_pad($invoiceNumber, 9, 0, STR_PAD_LEFT);
@@ -176,7 +176,7 @@ protected static function generateKey(
     /**
      * {@inheritdoc}
      */
-    public function format()
+    public function format() : string
     {
         return trim(preg_replace(self::REGEX, self::MASK, "{$this}"));
     }
@@ -184,7 +184,7 @@ public function format()
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         return self::calculateDigitFrom($baseNumber);
     }
@@ -198,7 +198,7 @@ public function calculateDigit($baseNumber)
      *
      * @return string
      */
-    public static function calculateDigitFrom($baseNumber)
+    public static function calculateDigitFrom(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/Sped/CTe.php b/src/Sped/CTe.php
index 58e87ca..24b9a69 100644
--- a/src/Sped/CTe.php
+++ b/src/Sped/CTe.php
@@ -8,7 +8,7 @@ final class CTe extends AbstractAccessKey
 {
     const LABEL = 'CTe';
 
-    protected function defaultModel()
+    protected function defaultModel() : Model
     {
         return Model::CTe();
     }
@@ -27,14 +27,14 @@ protected function defaultModel()
      * @return NFe
      */
     public static function generate(
-        $state,
+        int $state,
         \DateTime $generatedAt,
         Cnpj $cnpj,
-        $sequence,
-        $invoiceNumber,
+        int $sequence,
+        int $invoiceNumber,
         EmissionType $emissionType,
-        $controlNumber
-    ) {
+        int $controlNumber
+    ) : AbstractAccessKey {
         $accessKey = self::generateKey(
             $state,
             $generatedAt,
diff --git a/src/Sped/CTeOther.php b/src/Sped/CTeOther.php
index 75a22a8..9efb3f6 100644
--- a/src/Sped/CTeOther.php
+++ b/src/Sped/CTeOther.php
@@ -8,7 +8,7 @@ final class CTeOther extends AbstractAccessKey
 {
     const LABEL = 'CTeOther';
 
-    protected function defaultModel()
+    protected function defaultModel() : Model
     {
         return Model::CTeOther();
     }
@@ -27,14 +27,14 @@ protected function defaultModel()
      * @return NFe
      */
     public static function generate(
-        $state,
+        int $state,
         \DateTime $generatedAt,
         Cnpj $cnpj,
-        $sequence,
-        $invoiceNumber,
+        int $sequence,
+        int $invoiceNumber,
         EmissionType $emissionType,
-        $controlNumber
-    ) {
+        int $controlNumber
+    ) : AbstractAccessKey {
         $accessKey = self::generateKey(
             $state,
             $generatedAt,
diff --git a/src/Sped/EmissionType.php b/src/Sped/EmissionType.php
index d0462fa..d8946d2 100644
--- a/src/Sped/EmissionType.php
+++ b/src/Sped/EmissionType.php
@@ -37,55 +37,55 @@ class EmissionType
      *
      * @param int $type
      */
-    public function __construct($type)
+    public function __construct(int $type)
     {
         $this->validate($type);
-        $this->type = (int) $type;
+        $this->type = $type;
     }
 
-    private function validate($type)
+    private function validate(int $type)
     {
         if (!in_array($type, $this->allowed)) {
             throw InvalidEmissionType::notAllowed($type);
         }
     }
 
-    public static function normal()
+    public static function normal() : EmissionType
     {
         return new self(self::NORMAL);
     }
 
-    public static function contingencyDpec()
+    public static function contingencyDpec() : EmissionType
     {
         return new self(self::CONTINGENCY_DPEC);
     }
 
-    public static function contingencySVCRS()
+    public static function contingencySVCRS() : EmissionType
     {
         return new self(self::CONTINGENCY_SVCRS);
     }
 
-    public static function contingencySVCAN()
+    public static function contingencySVCAN() : EmissionType
     {
         return new self(self::CONTINGENCY_SVCAN);
     }
 
-    public static function contingencySCAN()
+    public static function contingencySCAN() : EmissionType
     {
         return new self(self::CONTINGENCY_SCAN);
     }
 
-    public static function contingencyOnSafetyForm()
+    public static function contingencyOnSafetyForm() : EmissionType
     {
         return new self(self::CONTINGENCY_ON_SAFETY_FORM);
     }
 
-    public static function contingencyOnSafetyFormFSDA()
+    public static function contingencyOnSafetyFormFSDA() : EmissionType
     {
         return new self(self::CONTINGENCY_ON_SAFETY_FORM_FSDA);
     }
 
-    public function __toString()
+    public function __toString() : string
     {
         return "{$this->type}";
     }
diff --git a/src/Sped/MDFe.php b/src/Sped/MDFe.php
index d43b813..d8d4e0c 100644
--- a/src/Sped/MDFe.php
+++ b/src/Sped/MDFe.php
@@ -8,7 +8,7 @@ final class MDFe extends AbstractAccessKey
 {
     const LABEL = 'MDFe';
 
-    protected function defaultModel()
+    protected function defaultModel() : Model
     {
         return Model::MDFe();
     }
@@ -27,14 +27,14 @@ protected function defaultModel()
      * @return NFe
      */
     public static function generate(
-        $state,
+        int $state,
         \DateTime $generatedAt,
         Cnpj $cnpj,
-        $sequence,
-        $invoiceNumber,
+        int $sequence,
+        int $invoiceNumber,
         EmissionType $emissionType,
-        $controlNumber
-    ) {
+        int $controlNumber
+    ) : AbstractAccessKey {
         $accessKey = self::generateKey(
             $state,
             $generatedAt,
diff --git a/src/Sped/Model.php b/src/Sped/Model.php
index b6fcf1a..d014e9e 100644
--- a/src/Sped/Model.php
+++ b/src/Sped/Model.php
@@ -31,50 +31,50 @@ class Model
      *
      * @param int $model
      */
-    public function __construct($model)
+    public function __construct(int $model)
     {
         $this->validate($model);
-        $this->model = (int) $model;
+        $this->model = $model;
     }
 
-    private function validate($model)
+    private function validate(int $model)
     {
         if (!in_array($model, $this->allowed)) {
             throw InvalidModel::notAllowed($model);
         }
     }
 
-    public static function NFe()
+    public static function NFe() : Model
     {
         return new self(self::TYPE_NFE);
     }
 
-    public static function NFCe()
+    public static function NFCe() : Model
     {
         return new self(self::TYPE_NFCE);
     }
 
-    public static function CTe()
+    public static function CTe() : Model
     {
         return new self(self::TYPE_CTE);
     }
 
-    public static function CTeOther()
+    public static function CTeOther() : Model
     {
         return new self(self::TYPE_CTE_OTHER);
     }
 
-    public static function MDFe()
+    public static function MDFe() : Model
     {
         return new self(self::TYPE_MDFE);
     }
 
-    public function equalsTo(Model $model)
+    public function equalsTo(Model $model) : bool
     {
         return $this->model === $model->model;
     }
 
-    public function __toString()
+    public function __toString() : string
     {
         return "{$this->model}";
     }
diff --git a/src/Sped/NFCe.php b/src/Sped/NFCe.php
index 91c73d0..f6782f7 100644
--- a/src/Sped/NFCe.php
+++ b/src/Sped/NFCe.php
@@ -8,7 +8,7 @@ final class NFCe extends AbstractAccessKey
 {
     const LABEL = 'NFCe';
 
-    protected function defaultModel()
+    protected function defaultModel() : Model
     {
         return Model::NFCe();
     }
@@ -27,14 +27,14 @@ protected function defaultModel()
      * @return NFe
      */
     public static function generate(
-        $state,
+        int $state,
         \DateTime $generatedAt,
         Cnpj $cnpj,
-        $sequence,
-        $invoiceNumber,
+        int $sequence,
+        int $invoiceNumber,
         EmissionType $emissionType,
-        $controlNumber
-    ) {
+        int $controlNumber
+    ) : AbstractAccessKey {
         $accessKey = self::generateKey(
             $state,
             $generatedAt,
diff --git a/src/Sped/NFe.php b/src/Sped/NFe.php
index c316f49..905a6a0 100644
--- a/src/Sped/NFe.php
+++ b/src/Sped/NFe.php
@@ -8,7 +8,7 @@ final class NFe extends AbstractAccessKey
 {
     const LABEL = 'NFe';
 
-    protected function defaultModel()
+    protected function defaultModel() : Model
     {
         return Model::NFe();
     }
@@ -27,14 +27,14 @@ protected function defaultModel()
      * @return NFe
      */
     public static function generate(
-        $state,
+        int $state,
         \DateTime $generatedAt,
         Cnpj $cnpj,
-        $sequence,
-        $invoiceNumber,
+        int $sequence,
+        int $invoiceNumber,
         EmissionType $emissionType,
-        $controlNumber
-    ) {
+        int $controlNumber
+    ) : AbstractAccessKey {
         $accessKey = self::generateKey(
             $state,
             $generatedAt,
diff --git a/src/StateRegistration.php b/src/StateRegistration.php
index 03604ff..d5346ae 100644
--- a/src/StateRegistration.php
+++ b/src/StateRegistration.php
@@ -81,7 +81,7 @@ final class StateRegistration extends AbstractDocument
      * @param string $number
      * @param StateRegistration\StateInterface $state
      */
-    public function __construct($number, StateRegistration\StateInterface $state)
+    public function __construct(string $number, StateRegistration\StateInterface $state)
     {
         $number = $state->normalizeNumber($number);
         $this->state = $state;
@@ -96,7 +96,7 @@ public function __construct($number, StateRegistration\StateInterface $state)
      *
      * @return AbstractDocument|boolean Returns a new Document instance or FALSE on failure.
      */
-    public static function createFromString($number, $state = '')
+    public static function createFromString(string $number, string $state = '')
     {
         try {
             return static::$state($number);
@@ -113,7 +113,7 @@ public static function createFromString($number, $state = '')
      *
      * @throws \ReflectionException
      */
-    public static function __callStatic($name, $arguments)
+    public static function __callStatic(string $name, array $arguments)
     {
         $class = self::$availableStates[$name];
         $reflection = new \ReflectionClass($class);
@@ -127,7 +127,7 @@ public static function __callStatic($name, $arguments)
     /**
      * {@inheritdoc}
      */
-    protected function extractBaseNumber($number)
+    protected function extractBaseNumber(string $number) : string
     {
         return $this->state->extractBaseNumber($number);
     }
@@ -135,7 +135,7 @@ protected function extractBaseNumber($number)
     /**
      * {@inheritdoc}
      */
-    protected function extractCheckerDigit($number)
+    protected function extractCheckerDigit(string $number) : string
     {
         return $this->state->extractCheckerDigit($number);
     }
@@ -145,7 +145,7 @@ protected function extractCheckerDigit($number)
      *
      * @return string Returns only numbers.
      */
-    public function format()
+    public function format() : string
     {
         return preg_replace($this->state->getRegex(), $this->state->getFormat(), "{$this}");
     }
@@ -153,7 +153,7 @@ public function format()
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $digit = $this->state->calculateDigit($baseNumber);
 
diff --git a/src/StateRegistration/Acre.php b/src/StateRegistration/Acre.php
index a16057b..561cd4a 100644
--- a/src/StateRegistration/Acre.php
+++ b/src/StateRegistration/Acre.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_AC.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Alagoas.php b/src/StateRegistration/Alagoas.php
index 086bcfe..b136bd1 100644
--- a/src/StateRegistration/Alagoas.php
+++ b/src/StateRegistration/Alagoas.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_AL.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Amapa.php b/src/StateRegistration/Amapa.php
index a418b10..a317909 100644
--- a/src/StateRegistration/Amapa.php
+++ b/src/StateRegistration/Amapa.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_AP.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $number = intval($baseNumber);
         $lastDigit = $this->discoverLastDigit($number);
@@ -53,7 +53,7 @@ public function calculateDigit($baseNumber)
      *
      * @return string
      */
-    private function discoverLastDigit($number)
+    private function discoverLastDigit(int $number) : string
     {
         $lastDigit = '0';
         if ($this->isBetweenFirstSlice($number)) {
@@ -69,11 +69,11 @@ private function discoverLastDigit($number)
     /**
      * Discover digit to be replaced based on number threshold.
      *
-     * @param $number
+     * @param int $number
      *
      * @return string
      */
-    private function discoverDigitToReplace($number)
+    private function discoverDigitToReplace(int $number) : string
     {
         $replaceDigit = '0';
         if ($this->isBetweenSecondSlice($number)) {
@@ -90,7 +90,7 @@ private function discoverDigitToReplace($number)
      *
      * @return bool
      */
-    private function isBetweenFirstSlice($number)
+    private function isBetweenFirstSlice(int $number) : bool
     {
         return (3000001 <= $number && $number <= 3017000);
     }
@@ -102,7 +102,7 @@ private function isBetweenFirstSlice($number)
      *
      * @return bool
      */
-    private function isBetweenSecondSlice($number)
+    private function isBetweenSecondSlice(int $number) : bool
     {
         return (3017001 <= $number && $number <= 3019022);
     }
diff --git a/src/StateRegistration/Amazonas.php b/src/StateRegistration/Amazonas.php
index dd1a3ce..6c9d9d4 100644
--- a/src/StateRegistration/Amazonas.php
+++ b/src/StateRegistration/Amazonas.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_AM.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Bahia.php b/src/StateRegistration/Bahia.php
index ff63dc8..fe86901 100644
--- a/src/StateRegistration/Bahia.php
+++ b/src/StateRegistration/Bahia.php
@@ -27,7 +27,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function normalizeNumber($number)
+    public function normalizeNumber(string $number) : string
     {
         if (!empty($number)) {
             return str_pad(parent::normalizeNumber($number), $this->getLength(), '0', STR_PAD_LEFT);
@@ -41,7 +41,7 @@ public function normalizeNumber($number)
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_BA.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Ceara.php b/src/StateRegistration/Ceara.php
index 7b20d80..43b3f66 100644
--- a/src/StateRegistration/Ceara.php
+++ b/src/StateRegistration/Ceara.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_CE.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/DistritoFederal.php b/src/StateRegistration/DistritoFederal.php
index 0ebfa04..fc94580 100644
--- a/src/StateRegistration/DistritoFederal.php
+++ b/src/StateRegistration/DistritoFederal.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_DF.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/EspiritoSanto.php b/src/StateRegistration/EspiritoSanto.php
index 7fb796c..a48a8da 100644
--- a/src/StateRegistration/EspiritoSanto.php
+++ b/src/StateRegistration/EspiritoSanto.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_ES.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Goias.php b/src/StateRegistration/Goias.php
index 8209b9e..56bdd1c 100644
--- a/src/StateRegistration/Goias.php
+++ b/src/StateRegistration/Goias.php
@@ -34,7 +34,7 @@ public function __construct()
      *
      * @return Goias
      */
-    private function setCurrentDigit($digit)
+    private function setCurrentDigit(string $digit)
     {
         $this->digit = $digit;
 
@@ -46,7 +46,7 @@ private function setCurrentDigit($digit)
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_GO.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $digitToReplace = $this->discoverDigitToReplace(intval($baseNumber));
 
@@ -74,7 +74,7 @@ public function calculateDigit($baseNumber)
      *
      * @return bool Returns true if number is magic, otherwise false.
      */
-    private function isMagicNumber($number)
+    private function isMagicNumber(string $number) : bool
     {
         return $number == '11094402';
     }
@@ -86,7 +86,7 @@ private function isMagicNumber($number)
      *
      * @return string
      */
-    private function fixedDigitForMagicNumber($digit)
+    private function fixedDigitForMagicNumber(string $digit) : string
     {
         if ($digit == $this->digit && $digit == '0') {
             return '0';
@@ -95,7 +95,7 @@ private function fixedDigitForMagicNumber($digit)
         return '1';
     }
 
-    private function discoverDigitToReplace($number)
+    private function discoverDigitToReplace(string $number) : string
     {
         $digitToReplace = '0';
         if ((10103105 <= $number) && ($number <= 10119997)) {
@@ -105,7 +105,7 @@ private function discoverDigitToReplace($number)
         return $digitToReplace;
     }
 
-    public function normalizeNumber($number)
+    public function normalizeNumber(string $number) : string
     {
         $number = parent::normalizeNumber($number);
         $this->setCurrentDigit(substr($number, -($this->getNumberOfDigits())));
diff --git a/src/StateRegistration/Maranhao.php b/src/StateRegistration/Maranhao.php
index c53aed1..f018792 100644
--- a/src/StateRegistration/Maranhao.php
+++ b/src/StateRegistration/Maranhao.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_MA.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/MatoGrosso.php b/src/StateRegistration/MatoGrosso.php
index a57887a..61c77ec 100644
--- a/src/StateRegistration/MatoGrosso.php
+++ b/src/StateRegistration/MatoGrosso.php
@@ -23,7 +23,7 @@ public function __construct()
         parent::__construct(self::LONG_NAME, self::LENGTH, self::NUMBER_OF_DIGITS, self::REGEX, self::FORMAT);
     }
 
-    public function normalizeNumber($number)
+    public function normalizeNumber(string $number) : string
     {
         if (!empty($number)) {
             return str_pad(parent::normalizeNumber($number), $this->getLength(), '0', STR_PAD_LEFT);
@@ -37,7 +37,7 @@ public function normalizeNumber($number)
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_MT.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/MatoGrossoSul.php b/src/StateRegistration/MatoGrossoSul.php
index 4f7cfcd..d6a4f48 100644
--- a/src/StateRegistration/MatoGrossoSul.php
+++ b/src/StateRegistration/MatoGrossoSul.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_MS.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/MinasGerais.php b/src/StateRegistration/MinasGerais.php
index 7635228..5126820 100644
--- a/src/StateRegistration/MinasGerais.php
+++ b/src/StateRegistration/MinasGerais.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_MG.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Para.php b/src/StateRegistration/Para.php
index cf0069a..8029b7a 100644
--- a/src/StateRegistration/Para.php
+++ b/src/StateRegistration/Para.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_PA.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Paraiba.php b/src/StateRegistration/Paraiba.php
index 42a4b7e..c476ae9 100644
--- a/src/StateRegistration/Paraiba.php
+++ b/src/StateRegistration/Paraiba.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_PB.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Parana.php b/src/StateRegistration/Parana.php
index ab65226..aba4588 100644
--- a/src/StateRegistration/Parana.php
+++ b/src/StateRegistration/Parana.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_PR.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Pernambuco.php b/src/StateRegistration/Pernambuco.php
index 691efc9..bd98f62 100644
--- a/src/StateRegistration/Pernambuco.php
+++ b/src/StateRegistration/Pernambuco.php
@@ -24,7 +24,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function getState()
+    public function getState() : string
     {
         return $this->calculation->getState();
     }
@@ -32,7 +32,7 @@ public function getState()
     /**
      * {@inheritdoc}
      */
-    public function normalizeNumber($number)
+    public function normalizeNumber(string $number) : string
     {
         $this->defineStrategy($number);
 
@@ -42,7 +42,7 @@ public function normalizeNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function getLength()
+    public function getLength() : int
     {
         return $this->calculation->getLength();
     }
@@ -50,7 +50,7 @@ public function getLength()
     /**
      * {@inheritdoc}
      */
-    public function getFormat()
+    public function getFormat() : string
     {
         return $this->calculation->getFormat();
     }
@@ -58,7 +58,7 @@ public function getFormat()
     /**
      * {@inheritdoc}
      */
-    public function getNumberOfDigits()
+    public function getNumberOfDigits() : int
     {
         return $this->calculation->getNumberOfDigits();
     }
@@ -66,7 +66,7 @@ public function getNumberOfDigits()
     /**
      * {@inheritdoc}
      */
-    public function getRegex()
+    public function getRegex() : string
     {
         return $this->calculation->getRegex();
     }
@@ -76,7 +76,7 @@ public function getRegex()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_PE.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         return $this->calculation->calculateDigit($baseNumber);
     }
@@ -84,7 +84,7 @@ public function calculateDigit($baseNumber)
     /**
      * {@inheritdoc}
      */
-    public function extractBaseNumber($number)
+    public function extractBaseNumber(string $number) : string
     {
         return $this->calculation->extractBaseNumber($number);
     }
@@ -92,7 +92,7 @@ public function extractBaseNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function extractCheckerDigit($number)
+    public function extractCheckerDigit(string $number) : string
     {
         return $this->calculation->extractCheckerDigit($number);
     }
@@ -102,7 +102,7 @@ public function extractCheckerDigit($number)
      *
      * @param string $number Number of document.
      */
-    private function defineStrategy($number)
+    private function defineStrategy(string $number)
     {
         $number = preg_replace('/\D/', '', $number);
         if ($this->calculation->getLength() != strlen($number)) {
diff --git a/src/StateRegistration/Pernambuco/EFisco.php b/src/StateRegistration/Pernambuco/EFisco.php
index b482be9..9d407ec 100644
--- a/src/StateRegistration/Pernambuco/EFisco.php
+++ b/src/StateRegistration/Pernambuco/EFisco.php
@@ -26,7 +26,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_PE.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Pernambuco/Old.php b/src/StateRegistration/Pernambuco/Old.php
index 0bf152e..e66aa55 100644
--- a/src/StateRegistration/Pernambuco/Old.php
+++ b/src/StateRegistration/Pernambuco/Old.php
@@ -26,7 +26,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_PE.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber . '0');
         $calculator->withMultipliersInterval(1, 9);
diff --git a/src/StateRegistration/Piaui.php b/src/StateRegistration/Piaui.php
index 0f05324..6c8d4c7 100644
--- a/src/StateRegistration/Piaui.php
+++ b/src/StateRegistration/Piaui.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_PI.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/RioDeJaneiro.php b/src/StateRegistration/RioDeJaneiro.php
index 146988d..b1a20bf 100644
--- a/src/StateRegistration/RioDeJaneiro.php
+++ b/src/StateRegistration/RioDeJaneiro.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_RJ.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/RioGrandeDoNorte.php b/src/StateRegistration/RioGrandeDoNorte.php
index 6a250da..79b5134 100644
--- a/src/StateRegistration/RioGrandeDoNorte.php
+++ b/src/StateRegistration/RioGrandeDoNorte.php
@@ -48,7 +48,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function normalizeNumber($number)
+    public function normalizeNumber(string $number) : string
     {
         $number = parent::normalizeNumber($number);
 
@@ -57,12 +57,12 @@ public function normalizeNumber($number)
         return $number;
     }
 
-    public function getFormat()
+    public function getFormat() : string
     {
         return $this->format;
     }
 
-    public function getLength()
+    public function getLength() : int
     {
         return $this->length;
     }
@@ -70,7 +70,7 @@ public function getLength()
     /**
      * @return string
      */
-    public function getRegex()
+    public function getRegex() : string
     {
         return $this->regex;
     }
@@ -80,7 +80,7 @@ public function getRegex()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_RN.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
@@ -96,7 +96,7 @@ public function calculateDigit($baseNumber)
     /**
      * @param string $number
      */
-    private function applyForNineDigits($number)
+    private function applyForNineDigits(string $number)
     {
         if (strlen($number) != self::LENGTH) {
             $this->format = self::FORMAT_FOR_NINE_NUMBERS;
diff --git a/src/StateRegistration/RioGrandeDoSul.php b/src/StateRegistration/RioGrandeDoSul.php
index 04c8162..e455e4b 100644
--- a/src/StateRegistration/RioGrandeDoSul.php
+++ b/src/StateRegistration/RioGrandeDoSul.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_RS.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Rondonia.php b/src/StateRegistration/Rondonia.php
index 10ff53d..3897acd 100644
--- a/src/StateRegistration/Rondonia.php
+++ b/src/StateRegistration/Rondonia.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_RO.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/Roraima.php b/src/StateRegistration/Roraima.php
index e0cb7a7..7183681 100644
--- a/src/StateRegistration/Roraima.php
+++ b/src/StateRegistration/Roraima.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_RR.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->withMultipliers([8, 7, 6, 5, 4, 3, 2, 1]);
diff --git a/src/StateRegistration/SantaCatarina.php b/src/StateRegistration/SantaCatarina.php
index 077dc37..1f44290 100644
--- a/src/StateRegistration/SantaCatarina.php
+++ b/src/StateRegistration/SantaCatarina.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_SC.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/SaoPaulo.php b/src/StateRegistration/SaoPaulo.php
index 36234e2..0a221d5 100644
--- a/src/StateRegistration/SaoPaulo.php
+++ b/src/StateRegistration/SaoPaulo.php
@@ -24,7 +24,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function normalizeNumber($number)
+    public function normalizeNumber(string $number) : string
     {
         $this->defineStrategy($number);
 
@@ -36,7 +36,7 @@ public function normalizeNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function getState()
+    public function getState() : string
     {
         return $this->calculation->getState();
     }
@@ -44,7 +44,7 @@ public function getState()
     /**
      * {@inheritdoc}
      */
-    public function extractBaseNumber($number)
+    public function extractBaseNumber(string $number) : string
     {
         return $this->calculation->extractBaseNumber($number);
     }
@@ -52,7 +52,7 @@ public function extractBaseNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function extractCheckerDigit($number)
+    public function extractCheckerDigit(string $number) : string
     {
         return $this->calculation->extractCheckerDigit($number);
     }
@@ -60,7 +60,7 @@ public function extractCheckerDigit($number)
     /**
      * {@inheritdoc}
      */
-    public function getLength()
+    public function getLength() : int
     {
         return $this->calculation->getLength();
     }
@@ -68,7 +68,7 @@ public function getLength()
     /**
      * {@inheritdoc}
      */
-    public function getFormat()
+    public function getFormat() : string
     {
         return $this->calculation->getFormat();
     }
@@ -76,7 +76,7 @@ public function getFormat()
     /**
      * {@inheritdoc}
      */
-    public function getNumberOfDigits()
+    public function getNumberOfDigits() : int
     {
         return $this->calculation->getNumberOfDigits();
     }
@@ -84,7 +84,7 @@ public function getNumberOfDigits()
     /**
      * {@inheritdoc}
      */
-    public function getRegex()
+    public function getRegex() : string
     {
         return $this->calculation->getRegex();
     }
@@ -94,7 +94,7 @@ public function getRegex()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_SP.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         return $this->calculation->calculateDigit($baseNumber);
     }
@@ -104,7 +104,7 @@ public function calculateDigit($baseNumber)
      *
      * @param string $number Number of document.
      */
-    private function defineStrategy($number)
+    private function defineStrategy(string $number)
     {
         if (strpos($number, 'P') !== false) {
             $this->calculation = new Rural();
diff --git a/src/StateRegistration/SaoPaulo/Rural.php b/src/StateRegistration/SaoPaulo/Rural.php
index 560082a..9e669a2 100644
--- a/src/StateRegistration/SaoPaulo/Rural.php
+++ b/src/StateRegistration/SaoPaulo/Rural.php
@@ -24,7 +24,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function normalizeNumber($number)
+    public function normalizeNumber(string $number) : string
     {
         return 'P' . preg_replace('/[\D]/i', '', $number);
     }
@@ -32,7 +32,7 @@ public function normalizeNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function extractBaseNumber($number)
+    public function extractBaseNumber(string $number) : string
     {
         return substr($number, 1, self::LENGTH - 4);
     }
@@ -40,7 +40,7 @@ public function extractBaseNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function extractCheckerDigit($number)
+    public function extractCheckerDigit(string $number) : string
     {
         return substr($number, -4, 1);
     }
@@ -50,7 +50,7 @@ public function extractCheckerDigit($number)
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_SP.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->withMultipliers([10, 8, 7, 6, 5, 4, 3, 1]);
diff --git a/src/StateRegistration/SaoPaulo/Urban.php b/src/StateRegistration/SaoPaulo/Urban.php
index 4ff4b4c..4b4cebb 100644
--- a/src/StateRegistration/SaoPaulo/Urban.php
+++ b/src/StateRegistration/SaoPaulo/Urban.php
@@ -26,7 +26,7 @@ public function __construct()
      *
      * No extract any digit
      */
-    public function extractBaseNumber($number)
+    public function extractBaseNumber(string $number) : string
     {
         return $number;
     }
@@ -34,7 +34,7 @@ public function extractBaseNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function extractCheckerDigit($number)
+    public function extractCheckerDigit(string $number) : string
     {
         return substr($number, self::LENGTH - 4, 1) . substr($number, -1);
     }
@@ -44,7 +44,7 @@ public function extractCheckerDigit($number)
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_SP.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $firstBaseNumber = substr($baseNumber, 0, 8);
 
@@ -57,7 +57,7 @@ public function calculateDigit($baseNumber)
         return "{$firstDigit}{$secondDigit}";
     }
 
-    private function calculateFirstDigit($baseNumber)
+    private function calculateFirstDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->withMultipliers([10, 8, 7, 6, 5, 4, 3, 1]);
@@ -69,7 +69,7 @@ private function calculateFirstDigit($baseNumber)
         return "{$digit}";
     }
 
-    private function calculateSecondDigit($baseNumber)
+    private function calculateSecondDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->withMultipliersInterval(2, 10);
diff --git a/src/StateRegistration/Sergipe.php b/src/StateRegistration/Sergipe.php
index 958ca97..17f39f6 100644
--- a/src/StateRegistration/Sergipe.php
+++ b/src/StateRegistration/Sergipe.php
@@ -28,7 +28,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_SE.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/StateRegistration/State.php b/src/StateRegistration/State.php
index 04d5a6a..3953745 100644
--- a/src/StateRegistration/State.php
+++ b/src/StateRegistration/State.php
@@ -38,7 +38,7 @@ abstract class State implements StateInterface
      * @param string $regex
      * @param string $format
      */
-    public function __construct($state, $length, $numberOfDigits, $regex, $format)
+    public function __construct(string $state, int $length, int $numberOfDigits, string $regex, string $format)
     {
         $this->state = $state;
         $this->length = $length;
@@ -50,7 +50,7 @@ public function __construct($state, $length, $numberOfDigits, $regex, $format)
     /**
      * {@inheritdoc}
      */
-    public function getState()
+    public function getState() : string
     {
         return $this->state;
     }
@@ -58,7 +58,7 @@ public function getState()
     /**
      * {@inheritdoc}
      */
-    public function getLength()
+    public function getLength() : int
     {
         return $this->length;
     }
@@ -66,7 +66,7 @@ public function getLength()
     /**
      * {@inheritdoc}
      */
-    public function getRegex()
+    public function getRegex() : string
     {
         return $this->regex;
     }
@@ -74,7 +74,7 @@ public function getRegex()
     /**
      * {@inheritdoc}
      */
-    public function getFormat()
+    public function getFormat() : string
     {
         return $this->format;
     }
@@ -82,7 +82,7 @@ public function getFormat()
     /**
      * {@inheritdoc}
      */
-    public function getNumberOfDigits()
+    public function getNumberOfDigits() : int
     {
         return $this->numberOfDigits;
     }
@@ -90,7 +90,7 @@ public function getNumberOfDigits()
     /**
      * {@inheritdoc}
      */
-    public function normalizeNumber($number)
+    public function normalizeNumber(string $number) : string
     {
         return preg_replace('/\D/', '', $number);
     }
@@ -98,7 +98,7 @@ public function normalizeNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function extractBaseNumber($number)
+    public function extractBaseNumber(string $number) : string
     {
         return substr($number, 0, -($this->getNumberOfDigits()));
     }
@@ -106,7 +106,7 @@ public function extractBaseNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function extractCheckerDigit($number)
+    public function extractCheckerDigit(string $number) : string
     {
         return substr($number, -($this->getNumberOfDigits()));
     }
diff --git a/src/StateRegistration/StateInterface.php b/src/StateRegistration/StateInterface.php
index 62e1c9c..2efeee6 100644
--- a/src/StateRegistration/StateInterface.php
+++ b/src/StateRegistration/StateInterface.php
@@ -9,27 +9,27 @@ interface StateInterface extends DigitCalculable
     /**
      * @return string
      */
-    public function getState();
+    public function getState() : string;
 
     /**
      * @return int
      */
-    public function getLength();
+    public function getLength() : int;
 
     /**
      * @return string
      */
-    public function getRegex();
+    public function getRegex() : string;
 
     /**
      * @return string
      */
-    public function getFormat();
+    public function getFormat() : string;
 
     /**
      * @return int
      */
-    public function getNumberOfDigits();
+    public function getNumberOfDigits() : int;
 
     /**
      * Normalizes number removing non-digit chars.
@@ -38,7 +38,7 @@ public function getNumberOfDigits();
      *
      * @return string Returns only numbers.
      */
-    public function normalizeNumber($number);
+    public function normalizeNumber(string $number) : string;
 
     /**
      * Extracts base number from document number.
@@ -47,7 +47,7 @@ public function normalizeNumber($number);
      *
      * @return string Returns only base number without checker digit.
      */
-    public function extractBaseNumber($number);
+    public function extractBaseNumber(string $number) : string;
 
     /**
      * Extracts the checker digit from document number.
@@ -56,5 +56,5 @@ public function extractBaseNumber($number);
      *
      * @return string Returns only checker digit.
      */
-    public function extractCheckerDigit($number);
+    public function extractCheckerDigit(string $number) : string;
 }
diff --git a/src/StateRegistration/Tocantins.php b/src/StateRegistration/Tocantins.php
index 79eff7a..de52135 100644
--- a/src/StateRegistration/Tocantins.php
+++ b/src/StateRegistration/Tocantins.php
@@ -24,7 +24,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function getState()
+    public function getState() : string
     {
         return $this->calculation->getState();
     }
@@ -32,7 +32,7 @@ public function getState()
     /**
      * {@inheritdoc}
      */
-    public function getLength()
+    public function getLength() : int
     {
         return $this->calculation->getLength();
     }
@@ -40,7 +40,7 @@ public function getLength()
     /**
      * {@inheritdoc}
      */
-    public function getRegex()
+    public function getRegex() : string
     {
         return $this->calculation->getRegex();
     }
@@ -48,7 +48,7 @@ public function getRegex()
     /**
      * {@inheritdoc}
      */
-    public function getFormat()
+    public function getFormat() : string
     {
         return $this->calculation->getFormat();
     }
@@ -56,7 +56,7 @@ public function getFormat()
     /**
      * {@inheritdoc}
      */
-    public function getNumberOfDigits()
+    public function getNumberOfDigits() : int
     {
         return $this->calculation->getNumberOfDigits();
     }
@@ -64,7 +64,7 @@ public function getNumberOfDigits()
     /**
      * {@inheritdoc}
      */
-    public function normalizeNumber($number)
+    public function normalizeNumber(string $number) : string
     {
         $this->defineStrategy($number);
 
@@ -74,7 +74,7 @@ public function normalizeNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function extractBaseNumber($number)
+    public function extractBaseNumber(string $number) : string
     {
         return $this->calculation->extractBaseNumber($number);
     }
@@ -82,7 +82,7 @@ public function extractBaseNumber($number)
     /**
      * {@inheritdoc}
      */
-    public function extractCheckerDigit($number)
+    public function extractCheckerDigit(string $number) : string
     {
         return $this->calculation->extractCheckerDigit($number);
     }
@@ -92,7 +92,7 @@ public function extractCheckerDigit($number)
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_TO.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         return $this->calculation->calculateDigit($baseNumber);
     }
@@ -102,7 +102,7 @@ public function calculateDigit($baseNumber)
      *
      * @param string $number Number of document.
      */
-    private function defineStrategy($number)
+    private function defineStrategy(string $number)
     {
         $number = preg_replace('/\D/', '', $number);
         if (strlen($number) == 9) {
diff --git a/src/StateRegistration/Tocantins/Eleven.php b/src/StateRegistration/Tocantins/Eleven.php
index 0f34330..d62ba8c 100644
--- a/src/StateRegistration/Tocantins/Eleven.php
+++ b/src/StateRegistration/Tocantins/Eleven.php
@@ -24,7 +24,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function extractBaseNumber($number)
+    public function extractBaseNumber(string $number) : string
     {
         $baseNumber = parent::extractBaseNumber($number);
 
@@ -36,7 +36,7 @@ public function extractBaseNumber($number)
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_TO.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
@@ -56,7 +56,7 @@ public function calculateDigit($baseNumber)
      *
      * @return string Returns base number without fixed digits.
      */
-    private function removeFixedDigits($baseNumber)
+    private function removeFixedDigits(string $baseNumber) : string
     {
         return substr($baseNumber, 0, 2) . substr($baseNumber, 4);
     }
diff --git a/src/StateRegistration/Tocantins/Nine.php b/src/StateRegistration/Tocantins/Nine.php
index a3118d4..2dc1247 100644
--- a/src/StateRegistration/Tocantins/Nine.php
+++ b/src/StateRegistration/Tocantins/Nine.php
@@ -26,7 +26,7 @@ public function __construct()
      *
      * @see http://www.sintegra.gov.br/Cad_Estados/cad_TO.html
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator($baseNumber);
         $calculator->useComplementaryInsteadOfModule();
diff --git a/src/Voter.php b/src/Voter.php
index 6240b20..5a34a3c 100644
--- a/src/Voter.php
+++ b/src/Voter.php
@@ -21,7 +21,7 @@ final class Voter extends AbstractDocument
      * @param string $section [optional]
      * @param string $zone    [optional]
      */
-    public function __construct($number, $section = null, $zone = null)
+    public function __construct(string $number, string $section = null, string $zone = null)
     {
         $number = preg_replace('/\D/', '', $number);
         parent::__construct($number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
@@ -30,7 +30,7 @@ public function __construct($number, $section = null, $zone = null)
         $this->zone = str_pad($zone, 3, '0', STR_PAD_LEFT);
     }
 
-    public static function createFromString($number, $section = null, $zone = null)
+    public static function createFromString(string $number, string $section = null, string $zone = null)
     {
         return parent::tryCreateFromString(self::class, $number, self::LENGTH, self::NUMBER_OF_DIGITS, self::LABEL);
     }
@@ -40,7 +40,7 @@ public static function createFromString($number, $section = null, $zone = null)
      *
      * @return string Returns section.
      */
-    public function getSection()
+    public function getSection() : string
     {
         return $this->section;
     }
@@ -50,7 +50,7 @@ public function getSection()
      *
      * @return string Returns zone.
      */
-    public function getZone()
+    public function getZone() : string
     {
         return $this->zone;
     }
@@ -60,7 +60,7 @@ public function getZone()
      *
      * @return string Returns only numbers.
      */
-    public function format()
+    public function format() : string
     {
         return "{$this}";
     }
@@ -68,7 +68,7 @@ public function format()
     /**
      * {@inheritdoc}
      */
-    public function calculateDigit($baseNumber)
+    public function calculateDigit(string $baseNumber) : string
     {
         $firstDigit = $this->calculateFirstDigit($baseNumber);
         $secondDigit = $this->calculateSecondDigit("{$baseNumber}{$firstDigit}");
@@ -83,7 +83,7 @@ public function calculateDigit($baseNumber)
      *
      * @return string Returns the checker digit.
      */
-    private function calculateFirstDigit($baseNumber)
+    private function calculateFirstDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator(substr($baseNumber, 0, -2));
         $calculator->withMultipliers([9, 8, 7, 6, 5, 4, 3, 2]);
@@ -100,7 +100,7 @@ private function calculateFirstDigit($baseNumber)
      *
      * @return string Returns the checker digit.
      */
-    private function calculateSecondDigit($baseNumber)
+    private function calculateSecondDigit(string $baseNumber) : string
     {
         $calculator = new DigitCalculator(substr($baseNumber, -3));
         $calculator->withMultipliers([9, 8, 7]);
diff --git a/tests/CnhTest.php b/tests/CnhTest.php
index 2fb7113..d0ab911 100644
--- a/tests/CnhTest.php
+++ b/tests/CnhTest.php
@@ -2,21 +2,22 @@
 
 namespace Brazanation\Documents\Tests;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Cnh;
 
 class CnhTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new Cnh($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return Cnh::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['83592802666'],
@@ -24,14 +25,14 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['83592802666', '83592802666'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Cnh::LABEL, ''],
@@ -40,7 +41,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Cnh::LABEL, 1],
diff --git a/tests/CnpjTest.php b/tests/CnpjTest.php
index a5f3f42..2c97ec5 100644
--- a/tests/CnpjTest.php
+++ b/tests/CnpjTest.php
@@ -2,21 +2,22 @@
 
 namespace Brazanation\Documents\Tests;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Cnpj;
 
 class CnpjTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new Cnpj($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return Cnpj::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['99999090910270'],
@@ -24,7 +25,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['99999090910270', '99.999.090/9102-70'],
@@ -32,7 +33,7 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Cnpj::LABEL, ''],
@@ -41,7 +42,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Cnpj::LABEL, 1],
diff --git a/tests/CnsTest.php b/tests/CnsTest.php
index 7888204..1f03790 100644
--- a/tests/CnsTest.php
+++ b/tests/CnsTest.php
@@ -2,21 +2,22 @@
 
 namespace Brazanation\Documents\Tests;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Cns;
 
 class CnsTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new Cns($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return Cns::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['242912018460005'],
@@ -30,14 +31,14 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['242912018460005', '242 9120 1846 0005'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Cns::LABEL, ''],
@@ -46,7 +47,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Cns::LABEL, 1],
diff --git a/tests/CpfTest.php b/tests/CpfTest.php
index b4940b9..0844552 100644
--- a/tests/CpfTest.php
+++ b/tests/CpfTest.php
@@ -2,21 +2,22 @@
 
 namespace Brazanation\Documents\Tests;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Cpf;
 
 class CpfTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new Cpf($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return Cpf::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['06843273173'],
@@ -24,7 +25,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['06843273173', '068.432.731-73'],
@@ -32,7 +33,7 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Cpf::LABEL, ''],
@@ -41,7 +42,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Cpf::LABEL, 1],
diff --git a/tests/DigitCalculatorTest.php b/tests/DigitCalculatorTest.php
index 8a208f7..a8c1918 100644
--- a/tests/DigitCalculatorTest.php
+++ b/tests/DigitCalculatorTest.php
@@ -60,7 +60,7 @@ public function testCalculateDigitForSaoPauloIdentityCard($number, $digit)
         $this->assertEquals($digit, $calculator->calculate());
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['3999100100001200000351202000003910476618602', '3'],
diff --git a/tests/DocumentTestCase.php b/tests/DocumentTestCase.php
index 01853e5..8b40adf 100644
--- a/tests/DocumentTestCase.php
+++ b/tests/DocumentTestCase.php
@@ -13,49 +13,49 @@ abstract class DocumentTestCase extends TestCase
      *
      * @return AbstractDocument
      */
-    abstract public function createDocument($number);
+    abstract public function createDocument(string $number) : AbstractDocument;
 
     /**
      * @param string $number
      *
      * @return AbstractDocument|boolean
      */
-    abstract public function createDocumentFromString($number);
+    abstract public function createDocumentFromString(string $number);
 
     /**
      * Provides a list of valid numbers
      *
      * @return array
      */
-    abstract public function provideValidNumbers();
+    abstract public function provideValidNumbers() : array;
 
     /**
      * Provides a list of valid numbers and its formats.
      *
      * @return array
      */
-    abstract public function provideValidNumbersAndExpectedFormat();
+    abstract public function provideValidNumbersAndExpectedFormat() : array;
 
     /**
      * Provides a empty data
      *
      * @return array
      */
-    abstract public function provideEmptyData();
+    abstract public function provideEmptyData() : array;
 
     /**
      * Provides a list of invalid numbers
      *
      * @return array
      */
-    abstract public function provideInvalidNumber();
+    abstract public function provideInvalidNumber() : array;
 
     /**
      * @param string $number
      *
      * @dataProvider provideValidNumbers
      */
-    final public function testShouldCreateInstance($number)
+    final public function testShouldCreateInstance(string $number)
     {
         $document = $this->createDocument($number);
         $this->assertInstanceOf(AbstractDocument::class, $document);
@@ -67,7 +67,7 @@ final public function testShouldCreateInstance($number)
      *
      * @dataProvider provideValidNumbers
      */
-    final public function testShouldCreateInstanceFromString($number)
+    final public function testShouldCreateInstanceFromString(string $number)
     {
         $document = $this->createDocumentFromString($number);
         $this->assertInstanceOf(AbstractDocument::class, $document);
@@ -80,7 +80,7 @@ final public function testShouldCreateInstanceFromString($number)
      *
      * @dataProvider provideValidNumbersAndExpectedFormat
      */
-    final public function testShouldFormatDocument($number, $expectedFormat)
+    final public function testShouldFormatDocument(string $number, string $expectedFormat)
     {
         $document = $this->createDocument($number);
         $this->assertEquals($expectedFormat, $document->format());
@@ -92,44 +92,19 @@ final public function testShouldFormatDocument($number, $expectedFormat)
      *
      * @dataProvider provideValidNumbersAndExpectedFormat
      */
-    final public function testShouldFormatDocumentFromString($number, $expectedFormat)
+    final public function testShouldFormatDocumentFromString(string $number, string $expectedFormat)
     {
         $document = $this->createDocumentFromString($number);
         $this->assertEquals($expectedFormat, $document->format());
     }
 
-    /**
-     * @param string $documentType
-     * @param string $number
-     *
-     * @dataProvider provideEmptyData
-     */
-    final public function testShouldThrowExceptionForEmptyData($documentType, $number)
-    {
-        $this->expectException(InvalidDocument::class);
-        $this->expectExceptionMessage("The {$documentType} must not be empty");
-        $this->createDocument($number);
-    }
-
-    /**
-     * @param string $documentType
-     * @param string $number
-     *
-     * @dataProvider provideEmptyData
-     */
-    final public function testShouldReturnsFalseForEmptyData($documentType, $number)
-    {
-        $document = $this->createDocumentFromString($number);
-        $this->assertFalse($document, "Failed asserting that {$documentType} is not valid");
-    }
-
     /**
      * @param string $documentType
      * @param string $number
      *
      * @dataProvider provideInvalidNumber
      */
-    public function testShouldThrowExceptionForInvalidNumbers($documentType, $number)
+    public function testShouldThrowExceptionForInvalidNumbers(string $documentType, string $number)
     {
         $numberSanitized = preg_replace('/[^\dX]/i', '', $number);
         $this->expectException(InvalidDocument::class);
@@ -143,7 +118,7 @@ public function testShouldThrowExceptionForInvalidNumbers($documentType, $number
      *
      * @dataProvider provideInvalidNumber
      */
-    public function testShouldReturnsFalseForInvalidNumbers($documentType, $number)
+    public function testShouldReturnsFalseForInvalidNumbers(string $documentType, string $number)
     {
         $document = $this->createDocumentFromString($number);
         $this->assertFalse($document, "Failed asserting that {$documentType} is not valid");
diff --git a/tests/JudiciaryProcessTest.php b/tests/JudiciaryProcessTest.php
index 1e0bd03..ab45c6c 100644
--- a/tests/JudiciaryProcessTest.php
+++ b/tests/JudiciaryProcessTest.php
@@ -2,21 +2,22 @@
 
 namespace Brazanation\Documents\Tests;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\JudiciaryProcess;
 
 class JudiciaryProcessTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new JudiciaryProcess($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return JudiciaryProcess::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['0048032.98.2009.8.09'],
@@ -24,7 +25,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['0048032982009809', '0048032-98.2009.8.09.0000'],
@@ -32,7 +33,7 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [JudiciaryProcess::LABEL, ''],
@@ -41,7 +42,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [JudiciaryProcess::LABEL, 1],
diff --git a/tests/PisPasepTest.php b/tests/PisPasepTest.php
index f60bcd8..b94d59e 100644
--- a/tests/PisPasepTest.php
+++ b/tests/PisPasepTest.php
@@ -2,21 +2,22 @@
 
 namespace Brazanation\Documents\Tests;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\PisPasep;
 
 class PisPasepTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new PisPasep($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return PisPasep::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['51823129491'],
@@ -24,7 +25,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['51823129491', '518.23129.49-1'],
@@ -32,7 +33,7 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [PisPasep::LABEL, ''],
@@ -41,7 +42,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [PisPasep::LABEL, 1],
diff --git a/tests/RenavamTest.php b/tests/RenavamTest.php
index de4f9f9..104f07f 100644
--- a/tests/RenavamTest.php
+++ b/tests/RenavamTest.php
@@ -2,21 +2,22 @@
 
 namespace Brazanation\Documents\Tests;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Renavam;
 
 class RenavamTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new Renavam($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return Renavam::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['61855253306'],
@@ -25,14 +26,14 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['61855253306', '6185.525330-6'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Renavam::LABEL, ''],
@@ -40,7 +41,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Renavam::LABEL, '00000000001'],
diff --git a/tests/Sped/CTeOtherTest.php b/tests/Sped/CTeOtherTest.php
index c7f0198..3981d8f 100644
--- a/tests/Sped/CTeOtherTest.php
+++ b/tests/Sped/CTeOtherTest.php
@@ -2,6 +2,7 @@
 
 namespace Brazanation\Documents\Tests\Sped;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Cnpj;
 use Brazanation\Documents\Sped\CTeOther;
 use Brazanation\Documents\Sped\EmissionType;
@@ -9,31 +10,31 @@
 
 class CTeOtherTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new CTeOther($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return CTeOther::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['52060433009911002506670120000007801267301613'],
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['52060433009911002506670120000007801267301613', '5206 0433 0099 1100 2506 6701 2000 0007 8012 6730 1613'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [CTeOther::LABEL, ''],
@@ -42,7 +43,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [CTeOther::LABEL, str_pad('1', 44, 1)],
@@ -58,7 +59,7 @@ public function provideInvalidNumber()
         ];
     }
 
-    public function provideInvalidEmissionType()
+    public function provideInvalidEmissionType() : array
     {
         return [
             [CTeOther::LABEL, '52060433009911002506550120000007801267301613'],
diff --git a/tests/Sped/CTeTest.php b/tests/Sped/CTeTest.php
index 19774d8..7a7f0ed 100644
--- a/tests/Sped/CTeTest.php
+++ b/tests/Sped/CTeTest.php
@@ -2,6 +2,7 @@
 
 namespace Brazanation\Documents\Tests\Sped;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Cnpj;
 use Brazanation\Documents\Sped\CTe;
 use Brazanation\Documents\Sped\EmissionType;
@@ -9,31 +10,31 @@
 
 class CTeTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new CTe($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return CTe::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['52060433009911002506570120000007801267301610'],
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['52060433009911002506570120000007801267301610', '5206 0433 0099 1100 2506 5701 2000 0007 8012 6730 1610'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [CTe::LABEL, ''],
@@ -42,7 +43,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [CTe::LABEL, str_pad('1', 44, 1)],
@@ -58,7 +59,7 @@ public function provideInvalidNumber()
         ];
     }
 
-    public function provideInvalidEmissionType()
+    public function provideInvalidEmissionType() : array
     {
         return [
             [CTe::LABEL, '52060433009911002506550120000007801267301613'],
diff --git a/tests/Sped/MDFeTest.php b/tests/Sped/MDFeTest.php
index edcd20e..a77cc81 100644
--- a/tests/Sped/MDFeTest.php
+++ b/tests/Sped/MDFeTest.php
@@ -2,6 +2,7 @@
 
 namespace Brazanation\Documents\Tests\Sped;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Cnpj;
 use Brazanation\Documents\Sped\EmissionType;
 use Brazanation\Documents\Sped\MDFe;
@@ -9,31 +10,31 @@
 
 class MDFeTest extends TestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new MDFe($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return MDFe::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['52060433009911002506580120000007801267301614'],
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['52060433009911002506580120000007801267301614', '5206 0433 0099 1100 2506 5801 2000 0007 8012 6730 1614'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [MDFe::LABEL, ''],
@@ -42,7 +43,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [MDFe::LABEL, str_pad('1', 44, 1)],
@@ -58,7 +59,7 @@ public function provideInvalidNumber()
         ];
     }
 
-    public function provideInvalidEmissionType()
+    public function provideInvalidEmissionType() : array
     {
         return [
             [MDFe::LABEL, '52060433009911002506550120000007801267301613'],
diff --git a/tests/Sped/NFCeTest.php b/tests/Sped/NFCeTest.php
index ffc6c6e..32944dc 100644
--- a/tests/Sped/NFCeTest.php
+++ b/tests/Sped/NFCeTest.php
@@ -2,6 +2,7 @@
 
 namespace Brazanation\Documents\Tests\Sped;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Cnpj;
 use Brazanation\Documents\Sped\EmissionType;
 use Brazanation\Documents\Sped\NFCe;
@@ -9,31 +10,31 @@
 
 class NFCeTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new NFCe($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return NFCe::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['52060433009911002506650120000007802067301610'],
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['52060433009911002506650120000007802067301610', '5206 0433 0099 1100 2506 6501 2000 0007 8020 6730 1610'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [NFCe::LABEL, ''],
@@ -42,7 +43,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [NFCe::LABEL, str_pad('1', 44, 1)],
@@ -58,7 +59,7 @@ public function provideInvalidNumber()
         ];
     }
 
-    public function provideInvalidEmissionType()
+    public function provideInvalidEmissionType() : array
     {
         return [
             [NFCe::LABEL, '52060433009911002506550120000007801267301613'],
diff --git a/tests/Sped/NFeTest.php b/tests/Sped/NFeTest.php
index 57a4e01..cf92c44 100644
--- a/tests/Sped/NFeTest.php
+++ b/tests/Sped/NFeTest.php
@@ -2,6 +2,7 @@
 
 namespace Brazanation\Documents\Tests\Sped;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Cnpj;
 use Brazanation\Documents\Sped\EmissionType;
 use Brazanation\Documents\Sped\NFe;
@@ -9,17 +10,17 @@
 
 class NFeTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new NFe($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return NFe::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['52060433009911002506550120000007801267301613'],
@@ -28,14 +29,14 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['52060433009911002506550120000007801267301613', '5206 0433 0099 1100 2506 5501 2000 0007 8012 6730 1613'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [NFe::LABEL, ''],
@@ -44,7 +45,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [NFe::LABEL, str_pad('1', 44, 1)],
@@ -60,7 +61,7 @@ public function provideInvalidNumber()
         ];
     }
 
-    public function provideInvalidEmissionType()
+    public function provideInvalidEmissionType() : array
     {
         return [
             [NFe::LABEL, '52060433009911002506650120000007802067301610'],
diff --git a/tests/StateRegistration/AcreTest.php b/tests/StateRegistration/AcreTest.php
index 926884d..1a224ad 100644
--- a/tests/StateRegistration/AcreTest.php
+++ b/tests/StateRegistration/AcreTest.php
@@ -2,37 +2,38 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Acre;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class AcreTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return StateRegistration::AC($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Acre::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             'AC' => ['0100482300112'],
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['0100482300112', '01.004.823/001-12'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Acre::LONG_NAME, ''],
@@ -41,7 +42,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Acre::LONG_NAME, 1],
diff --git a/tests/StateRegistration/AlagoasTest.php b/tests/StateRegistration/AlagoasTest.php
index f86d4c4..607379f 100644
--- a/tests/StateRegistration/AlagoasTest.php
+++ b/tests/StateRegistration/AlagoasTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Alagoas;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class AlagoasTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return StateRegistration::AL($number);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Alagoas::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['240000048'],
@@ -29,7 +30,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['240000048', '24.000.004-8'],
@@ -40,14 +41,14 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Alagoas::LONG_NAME, 0],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Alagoas::LONG_NAME, 1],
diff --git a/tests/StateRegistration/AmapaTest.php b/tests/StateRegistration/AmapaTest.php
index 8535c10..9571d96 100644
--- a/tests/StateRegistration/AmapaTest.php
+++ b/tests/StateRegistration/AmapaTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Amapa;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class AmapaTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Amapa());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Amapa::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['03.012.345-9'],
@@ -26,21 +27,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['030123459', '03.012.345-9'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Amapa::LONG_NAME, 0],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Amapa::LONG_NAME, 1],
diff --git a/tests/StateRegistration/AmazonasTest.php b/tests/StateRegistration/AmazonasTest.php
index 5545fd2..b82080e 100644
--- a/tests/StateRegistration/AmazonasTest.php
+++ b/tests/StateRegistration/AmazonasTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Amazonas;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class AmazonasTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Amazonas());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Amazonas::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['04.345.678-2'],
@@ -29,21 +30,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['04.345.678-2', '04.345.678-2'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Amazonas::LONG_NAME, 0],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Amazonas::LONG_NAME, 1],
diff --git a/tests/StateRegistration/BahiaTest.php b/tests/StateRegistration/BahiaTest.php
index 4224ae9..d8fa066 100644
--- a/tests/StateRegistration/BahiaTest.php
+++ b/tests/StateRegistration/BahiaTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Bahia;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class BahiaTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Bahia());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Bahia::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['123456-63'],
@@ -37,7 +38,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['123456-63', '0123456-63'],
@@ -45,14 +46,14 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Bahia::LONG_NAME, 0],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Bahia::LONG_NAME, '000000001'],
diff --git a/tests/StateRegistration/CearaTest.php b/tests/StateRegistration/CearaTest.php
index d172508..79834db 100644
--- a/tests/StateRegistration/CearaTest.php
+++ b/tests/StateRegistration/CearaTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Ceara;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class CearaTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Ceara());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Ceara::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['06.998.161-2'],
@@ -28,7 +29,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['06.998.161-2', '06.998.161-2'],
@@ -36,14 +37,14 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Ceara::LONG_NAME, 0],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Ceara::LONG_NAME, '1'],
diff --git a/tests/StateRegistration/DistritoFederalTest.php b/tests/StateRegistration/DistritoFederalTest.php
index 21dda7d..bb0da92 100644
--- a/tests/StateRegistration/DistritoFederalTest.php
+++ b/tests/StateRegistration/DistritoFederalTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\DistritoFederal as DF;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class DistritoFederalTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new DF());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, DF::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['0714880000168'],
@@ -28,7 +29,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['0756855500115', '07.568555.001-15'],
@@ -37,7 +38,7 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [DF::LONG_NAME, ''],
@@ -46,7 +47,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [DF::LONG_NAME, 1],
diff --git a/tests/StateRegistration/EspiritoSantoTest.php b/tests/StateRegistration/EspiritoSantoTest.php
index 638db16..5acd71a 100644
--- a/tests/StateRegistration/EspiritoSantoTest.php
+++ b/tests/StateRegistration/EspiritoSantoTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\EspiritoSanto;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class EspiritoSantoTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new EspiritoSanto());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, EspiritoSanto::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['082260664'],
@@ -31,21 +32,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['082260664', '082.260.66-4'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [EspiritoSanto::LONG_NAME, 0],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [EspiritoSanto::LONG_NAME, '1'],
diff --git a/tests/StateRegistration/GoiasTest.php b/tests/StateRegistration/GoiasTest.php
index 562c189..36e980b 100644
--- a/tests/StateRegistration/GoiasTest.php
+++ b/tests/StateRegistration/GoiasTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Goias;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class GoiasTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Goias());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Goias::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['110944020'],
@@ -27,21 +28,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['109876547','10.987.654-7'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Goias::LONG_NAME, 0],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Goias::LONG_NAME, '1'],
diff --git a/tests/StateRegistration/MaranhaoTest.php b/tests/StateRegistration/MaranhaoTest.php
index 4e00c57..a5345cb 100644
--- a/tests/StateRegistration/MaranhaoTest.php
+++ b/tests/StateRegistration/MaranhaoTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Maranhao;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class MaranhaoTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Maranhao());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Maranhao::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['12.074072-9'],
@@ -26,21 +27,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['120000385','12.000.038-5'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Maranhao::LONG_NAME, 0],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Maranhao::LONG_NAME, '1'],
diff --git a/tests/StateRegistration/MatoGrossoSulTest.php b/tests/StateRegistration/MatoGrossoSulTest.php
index f3a43f9..02ecf16 100644
--- a/tests/StateRegistration/MatoGrossoSulTest.php
+++ b/tests/StateRegistration/MatoGrossoSulTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\MatoGrossoSul;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class MatoGrossoSulTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new MatoGrossoSul());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, MatoGrossoSul::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['28.322.235-2'],
@@ -38,14 +39,14 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['283222352', '28.322.235-2'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [MatoGrossoSul::LONG_NAME, 0],
@@ -54,7 +55,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [MatoGrossoSul::LONG_NAME, 1],
diff --git a/tests/StateRegistration/MatoGrossoTest.php b/tests/StateRegistration/MatoGrossoTest.php
index 5c9dd73..87b8280 100644
--- a/tests/StateRegistration/MatoGrossoTest.php
+++ b/tests/StateRegistration/MatoGrossoTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\MatoGrosso;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class MatoGrossoTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new MatoGrosso());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, MatoGrosso::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['0013193686-7'],
@@ -113,7 +114,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['00131936867', '0013193686-7'],
@@ -123,7 +124,7 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [MatoGrosso::LONG_NAME, 0],
@@ -132,7 +133,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [MatoGrosso::LONG_NAME, '11111111111'],
diff --git a/tests/StateRegistration/MinasGeraisTest.php b/tests/StateRegistration/MinasGeraisTest.php
index c4c8dae..e83e3ec 100644
--- a/tests/StateRegistration/MinasGeraisTest.php
+++ b/tests/StateRegistration/MinasGeraisTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\MinasGerais as MG;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class MinasGeraisTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new MG());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, MG::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['062.307.904/0081'],
@@ -28,7 +29,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['2080189746429', '208.018.974/6429'],
@@ -36,7 +37,7 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [MG::LONG_NAME, 0],
@@ -45,7 +46,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [MG::LONG_NAME, 1],
diff --git a/tests/StateRegistration/ParaTest.php b/tests/StateRegistration/ParaTest.php
index d742667..2f1cc63 100644
--- a/tests/StateRegistration/ParaTest.php
+++ b/tests/StateRegistration/ParaTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Para;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class ParaTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Para());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Para::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['15.229.851-7'],
@@ -34,21 +35,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['152298517', '15.229.851-7'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Para::LONG_NAME, null],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Para::LONG_NAME, '11111111111'],
diff --git a/tests/StateRegistration/ParaibaTest.php b/tests/StateRegistration/ParaibaTest.php
index cc7d661..e27265a 100644
--- a/tests/StateRegistration/ParaibaTest.php
+++ b/tests/StateRegistration/ParaibaTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Paraiba;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class ParaibaTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Paraiba());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Paraiba::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['16.030.321-4'],
@@ -125,21 +126,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['317806734', '31.780.673-4'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Paraiba::LONG_NAME, null],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Paraiba::LONG_NAME, '11111111111'],
diff --git a/tests/StateRegistration/ParanaTest.php b/tests/StateRegistration/ParanaTest.php
index 490028d..b182076 100644
--- a/tests/StateRegistration/ParanaTest.php
+++ b/tests/StateRegistration/ParanaTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Parana;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class ParanaTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Parana());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Parana::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['099.00004-09'],
@@ -35,21 +36,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['9025821693', '902.58216-93'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Parana::LONG_NAME, null],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Parana::LONG_NAME, '11111111111'],
diff --git a/tests/StateRegistration/PernambucoTest.php b/tests/StateRegistration/PernambucoTest.php
index 496085d..95b9441 100644
--- a/tests/StateRegistration/PernambucoTest.php
+++ b/tests/StateRegistration/PernambucoTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Pernambuco;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class PernambucoTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Pernambuco());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Pernambuco::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['18.1.001.0000004-9'],
@@ -31,7 +32,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['18100100000049', '18.1.001.0000004-9'],
@@ -39,14 +40,14 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Pernambuco::LONG_NAME, null],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Pernambuco::LONG_NAME, '11111111111'],
diff --git a/tests/StateRegistration/PiauiTest.php b/tests/StateRegistration/PiauiTest.php
index c9a5be5..e315ec3 100644
--- a/tests/StateRegistration/PiauiTest.php
+++ b/tests/StateRegistration/PiauiTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Piaui;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class PiauiTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Piaui());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Piaui::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['193016567'],
@@ -27,21 +28,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['193016567', '19.301.656-7'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Piaui::LONG_NAME, null],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Piaui::LONG_NAME, '11111111111'],
diff --git a/tests/StateRegistration/RioDeJaneiroTest.php b/tests/StateRegistration/RioDeJaneiroTest.php
index 82b2722..c4afad1 100644
--- a/tests/StateRegistration/RioDeJaneiroTest.php
+++ b/tests/StateRegistration/RioDeJaneiroTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\RioDeJaneiro;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class RioDeJaneiroTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new RioDeJaneiro());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, RioDeJaneiro::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['53.518.028'],
@@ -26,14 +27,14 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['53518028', '53.518.028'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [RioDeJaneiro::LONG_NAME, null],
@@ -42,7 +43,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [RioDeJaneiro::LONG_NAME, '11111111'],
diff --git a/tests/StateRegistration/RioGrandeDoNorteTest.php b/tests/StateRegistration/RioGrandeDoNorteTest.php
index dc8f304..2eb492a 100644
--- a/tests/StateRegistration/RioGrandeDoNorteTest.php
+++ b/tests/StateRegistration/RioGrandeDoNorteTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\RioGrandeDoNorte;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class RioGrandeDoNorteTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new RioGrandeDoNorte());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, RioGrandeDoNorte::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['20.040.040-1'],
@@ -32,7 +33,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['200400401', '20.040.040-1'],
@@ -41,14 +42,14 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [RioGrandeDoNorte::LONG_NAME, ''],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [RioGrandeDoNorte::LONG_NAME, '11111111'],
diff --git a/tests/StateRegistration/RioGrandeDoSulTest.php b/tests/StateRegistration/RioGrandeDoSulTest.php
index bd3094b..d23e27c 100644
--- a/tests/StateRegistration/RioGrandeDoSulTest.php
+++ b/tests/StateRegistration/RioGrandeDoSulTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\RioGrandeDoSul;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class RioGrandeDoSulTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new RioGrandeDoSul());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, RioGrandeDoSul::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['050/0068836'],
@@ -27,21 +28,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['0500068836', '050/0068836'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [RioGrandeDoSul::LONG_NAME, ''],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [RioGrandeDoSul::LONG_NAME, '1111111111'],
diff --git a/tests/StateRegistration/RondoniaTest.php b/tests/StateRegistration/RondoniaTest.php
index 44654ae..985ff99 100644
--- a/tests/StateRegistration/RondoniaTest.php
+++ b/tests/StateRegistration/RondoniaTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Rondonia;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class RondoniaTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Rondonia());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Rondonia::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['0000000172159-3'],
@@ -52,21 +53,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['00000001721593', '0000000172159-3'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Rondonia::LONG_NAME, ''],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Rondonia::LONG_NAME, '1111111111'],
diff --git a/tests/StateRegistration/RoraimaTest.php b/tests/StateRegistration/RoraimaTest.php
index 2a4a508..33974cd 100644
--- a/tests/StateRegistration/RoraimaTest.php
+++ b/tests/StateRegistration/RoraimaTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Roraima;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class RoraimaTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Roraima());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Roraima::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['24006628-1'],
@@ -35,21 +36,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['240066281', '24006628-1'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Roraima::LONG_NAME, ''],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Roraima::LONG_NAME, '1111111111'],
diff --git a/tests/StateRegistration/SantaCatarinaTest.php b/tests/StateRegistration/SantaCatarinaTest.php
index 8ecd895..c6be73f 100644
--- a/tests/StateRegistration/SantaCatarinaTest.php
+++ b/tests/StateRegistration/SantaCatarinaTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\SantaCatarina;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class SantaCatarinaTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new SantaCatarina());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, SantaCatarina::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['251040852'],
@@ -27,21 +28,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['251040852','251.040.852'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [SantaCatarina::LONG_NAME, ''],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [SantaCatarina::LONG_NAME, '1111111111'],
diff --git a/tests/StateRegistration/SaoPauloTest.php b/tests/StateRegistration/SaoPauloTest.php
index 7853bf6..0ca9d13 100644
--- a/tests/StateRegistration/SaoPauloTest.php
+++ b/tests/StateRegistration/SaoPauloTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\SaoPaulo;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class SaoPauloTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new SaoPaulo());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, SaoPaulo::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             'commercial-industrial' => ['110.042.490.114'],
@@ -26,7 +27,7 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             'commercial-industrial' => ['110042490114', '110.042.490.114'],
@@ -34,14 +35,14 @@ public function provideValidNumbersAndExpectedFormat()
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [SaoPaulo::LONG_NAME, ''],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [SaoPaulo::LONG_NAME, '1111111111'],
diff --git a/tests/StateRegistration/SergipeTest.php b/tests/StateRegistration/SergipeTest.php
index f1d177e..5cbd41d 100644
--- a/tests/StateRegistration/SergipeTest.php
+++ b/tests/StateRegistration/SergipeTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Sergipe;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class SergipeTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Sergipe());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Sergipe::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['44.250.767-4'],
@@ -26,21 +27,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['442507674', '44.250.767-4'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Sergipe::LONG_NAME, ''],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Sergipe::LONG_NAME, '1111111111'],
diff --git a/tests/StateRegistration/TocantinsTest.php b/tests/StateRegistration/TocantinsTest.php
index 341696c..da7e230 100644
--- a/tests/StateRegistration/TocantinsTest.php
+++ b/tests/StateRegistration/TocantinsTest.php
@@ -2,23 +2,24 @@
 
 namespace Brazanation\Documents\Tests\StateRegistration;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\StateRegistration;
 use Brazanation\Documents\StateRegistration\Tocantins;
 use Brazanation\Documents\Tests\DocumentTestCase;
 
 class TocantinsTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new StateRegistration($number, new Tocantins());
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return StateRegistration::createFromString($number, Tocantins::SHORT_NAME);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             ['29010227836'],
@@ -30,21 +31,21 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['29010227836', '29.01.022.783-6'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Tocantins::LONG_NAME, ''],
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Tocantins::LONG_NAME, '1111111111'],
diff --git a/tests/VoterTest.php b/tests/VoterTest.php
index 0ff8658..3017dda 100644
--- a/tests/VoterTest.php
+++ b/tests/VoterTest.php
@@ -2,21 +2,22 @@
 
 namespace Brazanation\Documents\Tests;
 
+use Brazanation\Documents\AbstractDocument;
 use Brazanation\Documents\Voter;
 
 class VoterTest extends DocumentTestCase
 {
-    public function createDocument($number)
+    public function createDocument(string $number) : AbstractDocument
     {
         return new Voter($number, null, null);
     }
 
-    public function createDocumentFromString($number)
+    public function createDocumentFromString(string $number)
     {
         return Voter::createFromString($number);
     }
 
-    public function provideValidNumbers()
+    public function provideValidNumbers() : array
     {
         return [
             'GO' => ['247003181023'],
@@ -28,14 +29,14 @@ public function provideValidNumbers()
         ];
     }
 
-    public function provideValidNumbersAndExpectedFormat()
+    public function provideValidNumbersAndExpectedFormat() : array
     {
         return [
             ['106644440302', '106644440302'],
         ];
     }
 
-    public function provideEmptyData()
+    public function provideEmptyData() : array
     {
         return [
             [Voter::LABEL, ''],
@@ -44,7 +45,7 @@ public function provideEmptyData()
         ];
     }
 
-    public function provideInvalidNumber()
+    public function provideInvalidNumber() : array
     {
         return [
             [Voter::LABEL, 1],