code: def by_resource_user_and_perm(
          cls, user_id, perm_name, resource_id, db_session=None
      ):
          
          db_session = get_db_session(db_session)
  
          query = db_session.query(cls.model).filter(cls.model.user_id == user_id)
          query = query.filter(cls.model.resource_id == resource_id)
          query = query.filter(cls.model.perm_name == perm_name)
          return query.first()
docs: return all instances by user name, perm name and resource id
  
          :param user_id:
          :param perm_name:
          :param resource_id:
          :param db_session:
          :return: