def METHOD_NAME(manager):
    manager.test_window("one")
    manager.test_window("two")
    manager.test_window("101")
    manager.test_window("102")
    manager.test_window("103")
    assert manager.c.layout.info()["client_trees"] == {
        "Foo": [["one"], ["two"], ["101"], ["102"], ["103"]],
        "Bar": [],
    }
    """
    # TODO how to serialize a function object? i.e. `sorter`:
    def sorter(window):
        try:
            if int(window.name) % 2 == 0:
                return 'Even'
            else:
                return 'Odd'
        except ValueError:
            return 'Bar'
    manager.c.layout.sort_windows(sorter)
    assert manager.c.layout.info()['client_trees'] == {
        'Foo': [],
        'Bar': [['one'], ['two']],
        'Even': [['102']],
        'Odd': [['101'], ['103']]
    }
    """