code: def word_groups_for_language(language_code):
      
  
      if language_code not in LANGUAGE_CODES:
          message = '{} is not an available language code'.format(language_code)
          raise InvalidLanguageCodeException(message)
  
      return MATH_WORDS[language_code]
docs: Return the math word groups for a language code.
      The language_code should be an ISO 639-2 language code.
      https://www.loc.gov/standards/iso639-2/php/code_list.php