Database client for accessing storage.

           :returns: :class:`livebridge.storages.base.BaseStorage`

def _db(self):
        """Database client for accessing storage.

           :returns: :class:`livebridge.storages.base.BaseStorage` """
        if not hasattr(self, "_db_client") or getattr(self, "_db_client") is None:
            self._db_client = get_db_client()
        return self._db_client