def METHOD_NAME(instance, aggregator):
    ibmdb2 = IbmDb2Check('ibm_db2', {}, [instance])
    ibmdb2._conn = mock.MagicMock()
    with mock.patch('ibm_db.exec_immediate'):
        ibmdb2.check(instance)
    aggregator.assert_service_check(IbmDb2Check.SERVICE_CHECK_CONNECT, IbmDb2Check.OK)