Fix german_transliterate module error

tensorflow_tts/utils/cleaners.py

@@ -24,7 +24,11 @@
 from tensorflow_tts.utils.korean import tokenize as ko_tokenize
 from tensorflow_tts.utils.number_norm import normalize_numbers
 from unidecode import unidecode
-from german_transliterate.core import GermanTransliterate
+
+try:
+    from german_transliterate.core import GermanTransliterate
+except:
+    pass
 
 # Regular expression matching whitespace:
 _whitespace_re = re.compile(r"\s+")
@@ -111,5 +115,8 @@ def korean_cleaners(text):
 
 def german_cleaners(text):
     """Pipeline for German text, including number and abbreviation expansion."""
-    text = GermanTransliterate(replace={';': ',', ':': ' '}, sep_abbreviation=' -- ').transliterate(text)
+    try:
+        text = GermanTransliterate(replace={';': ',', ':': ' '}, sep_abbreviation=' -- ').transliterate(text)
+    except NameError:
+        raise ModuleNotFoundError("Install german_transliterate package to use german_cleaners")
     return text