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