Restore a soft-deleted model instance.

def restore(self):
        """
        Restore a soft-deleted model instance.
        """
        if self._fire_model_event("restoring") is False:
            return False

        setattr(self, self.get_deleted_at_column(), None)

        self.set_exists(True)

        result = self.save()

        self._fire_model_event("restored")

        return result