Return a json dictionary representing this model.

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