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