Return a json dictionary representing this model.

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