def close(self):
        """Close and delete instance."""

        # remove callbacks
        DatastoreLegacy.datastores[self.domain].remove(self)

        # delete data after the last instance is gone
        if self.release_storage and \
           not DatastoreLegacy.datastores[self.domain]:
            del DatastoreLegacy.store[self.domain]

        del self
Close and delete instance.