def foo(a=None,b=None,c=None,d=None):
    a = 1
    print(a)

    a = 1, 2, 3
    print(a)

    a, b, c = 7, 8, 9
    print(a,b,c)

    a, b, a, b, a, b = 1, 2, 3, 4, 5, 6
    print(a,b,c)

    a, b, c = (4,5,6)
    print(a,b,c)

    class Thing:
        pass

    a = Thing()

    a.one, a.two, a.three = "日本語"
    print(a.one,a.two,a.three)

    d = a, b = c = [1,2]
    print(d,a,b,c)

    (a, b) = 45, 90
    print(a, b)

    (a, b) = (100, 200)
    print(a, b)

    (a, b,) = "extraneous", "commas"
    print(a, b)

    a, b, = "are", "weird"
    print(a, b)


foo()