Return a json dictionary representing this model.

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