a = Foo(
        "a": 4,
        "z": 2,
        [b, z],
        "hello, world",
        c
    )

Foo(a b, c d)

Foo(a, b)

Foo(a, [b, [2, 3] c], d)

Foo(
    a,
    [b, "c"],
    d
)

Foo(
    a,
    [b, c],
    d
)

Foo(
    a,
    [b, c],
    d
)