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