def element_for_writer(self, const):
        if const is enginefacade._WRITER:
            return self.writer
        elif const is enginefacade._READER:
            return self.reader
        elif const is enginefacade._ASYNC_READER:
            return self.async_reader
        else:
            assert False, "Unknown constant: %s" % const
dataset/ETHPy150Open openstack/oslo.db/oslo_db/tests/sqlalchemy/test_enginefacade.py/AssertDataSource.element_for_writer/original