docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self, 'feedback_type') and self.feedback_type is not None:
              _dict['feedback_type'] = self.feedback_type
          if hasattr(self, 'document') and self.document is not None:
              _dict['document'] = self.document._to_dict()
          if hasattr(self, 'model_id') and self.model_id is not None:
              _dict['model_id'] = self.model_id
          if hasattr(self, 'model_version') and self.model_version is not None:
              _dict['model_version'] = self.model_version
          if hasattr(self, 'location') and self.location is not None:
              _dict['location'] = self.location._to_dict()
          if hasattr(self, 'text') and self.text is not None:
              _dict['text'] = self.text
          if hasattr(self,
                     'original_labels') and self.original_labels is not None:
              _dict['original_labels'] = self.original_labels._to_dict()
          if hasattr(self, 'updated_labels') and self.updated_labels is not None:
              _dict['updated_labels'] = self.updated_labels._to_dict()
          if hasattr(self, 'pagination') and self.pagination is not None:
              _dict['pagination'] = self.pagination._to_dict()
          return _dict