def METHOD_NAME():
    '''Test that children cannot be added to StandaloneDirective.'''
    cdir = StandaloneDirective()
    schedule = Schedule()
    # test adding child
    with pytest.raises(GenerationError) as excinfo:
        cdir.addchild(schedule)
    assert ("Item 'Schedule' can't be child 0 of 'StandaloneDirective'. The "
            "valid format is: 'None'." in str(excinfo.value))