code: def get_one_for_update(self, object_id):
          
          return self.session.query(self.cls).with_for_update().filter_by(id=object_id).one()
docs: Retrieve an object by its object_id
          Does a select for update on the row, results in row level lock for the duration of the transaction
  
          :param object_id: the objects id.
          :return: the requested object
          :raises: :class: NoResultFound when the object could not be found