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