Sqlalchemy delete in subquery

InvalidRequestError: Could not evaluate current criteria in Python. Specify 'fetch' or False for the synchronize_session parameter.

sl = DBSession.query(Puesto.id).filter(Puesto.locales_id == id).subquery() DBSession.query(Servicio).filter(Servicio.puestos_id.in_(sl)) \ .delete(synchronize_session='fetch')

References :
python - Sqlalchemy delete subquery - Stack Overflow