docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self, 'word_count') and self.word_count is not None:
              _dict['word_count'] = self.word_count
          if hasattr(self,
                     'character_count') and self.character_count is not None:
              _dict['character_count'] = self.character_count
          if hasattr(self, 'translations') and self.translations is not None:
              _dict['translations'] = [x._to_dict() for x in self.translations]
          return _dict