def test_lattice_simple():
    assert Join(Join(2, 3), 4) == Join(2, Join(3, 4))
    assert Join(2, 3) == Join(3, 2)
    assert Join(0, 2) == 0
    assert Join(1, 2) == 2
    assert Join(2, 2) == 2

    assert Join(Join(2, 3), 4) == Join(2, 3, 4)
    assert Join() == 1
    assert Join(4) == 4
    assert Join(1, 4, 2, 3, 1, 3, 2) == Join(2, 3, 4)