Return a json dictionary representing this model.

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