docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self, 'transcript') and self.transcript is not None:
              _dict['transcript'] = self.transcript
          if hasattr(self, 'confidence') and self.confidence is not None:
              _dict['confidence'] = self.confidence
          if hasattr(self, 'timestamps') and self.timestamps is not None:
              _dict['timestamps'] = self.timestamps
          if hasattr(self,
                     'word_confidence') and self.word_confidence is not None:
              _dict['word_confidence'] = self.word_confidence
          return _dict