diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index 0ea6b4e..baffc36 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -26,7 +26,7 @@ public function getConfigTreeBuilder()
                     ->cannotBeEmpty()
                     ->isRequired()
                     ->children()
-                        ->scalarNode('from')->cannotBeEmpty()->isRequired()->end()
+                        ->variableNode('from')->cannotBeEmpty()->isRequired()->end()
                     ->end()
                 ->end()
                 ->arrayNode('cid')