def METHOD_NAME():
    a1 = ak.from_json("[[0.0, 1.1], null, [2.2, 3.3]]")
    a2 = ak.from_json("[[4.4, 5.5, 6.6], [7, 8, 9], [7.7, 8.8, 9.9]]")
    a1 = ak.to_regular(a1, axis=1)
    a2 = ak.to_regular(a2, axis=1)
    c = ak.concatenate([a1, a2], axis=1)
    assert c.to_list() == [
        [0.0, 1.1, 4.4, 5.5, 6.6],
        [7, 8, 9],
        [2.2, 3.3, 7.7, 8.8, 9.9],
    ]
    assert c.type == ArrayType(ListType(NumpyType("float64")), 3)