def _to_dict(self):
        """Return a json dictionary representing this model."""
        _dict = {}
        if hasattr(self, 'generic') and self.generic is not None:
            _dict['generic'] = [x._to_dict() for x in self.generic]
        if hasattr(self, 'intents') and self.intents is not None:
            _dict['intents'] = [x._to_dict() for x in self.intents]
        if hasattr(self, 'entities') and self.entities is not None:
            _dict['entities'] = [x._to_dict() for x in self.entities]
        if hasattr(self, 'actions') and self.actions is not None:
            _dict['actions'] = [x._to_dict() for x in self.actions]
        if hasattr(self, 'debug') and self.debug is not None:
            _dict['debug'] = self.debug._to_dict()
        if hasattr(self, 'user_defined') and self.user_defined is not None:
            _dict['user_defined'] = self.user_defined
        return _dict
Return a json dictionary representing this model.