code: def _get_stop_words(self, language):
          
          if language not in self.available_languages:
              raise StopWordError(
                  'Stop words are not available in "%s".\n'
                  'If possible do a pull request at : '
                  'https://github.com/Fantomas42/mots-vides' %
                  language)
          try:
              filename = self.get_collection_filename(language)
              collection = self.read_collection(filename)
          except IOError:
              raise StopWordError(
                  '"%s" file is unreadable, check your installation.' %
                  filename)
          return collection
docs: Internal method for getting the stop words collections
          and raising errors.