docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self, 'score') and self.score is not None:
              _dict['score'] = self.score
          if hasattr(self, 'sentence') and self.sentence is not None:
              _dict['sentence'] = self.sentence
          if hasattr(self, 'type') and self.type is not None:
              _dict['type'] = self.type
          if hasattr(self, 'arguments') and self.arguments is not None:
              _dict['arguments'] = [x._to_dict() for x in self.arguments]
          return _dict