def gen():
    yield 1
    yield 2
    yield 3


def normal():
    return 1
    return 2
    return 3


def main():
    print("=== print gen function ===")
    print(gen())

    print("=== print normal function ===")
    print(normal())

    print("=== print gen function in loop ===")
    for g in gen():
        print(g)

    print("=== print normal function in loop ===")
    for n in normal():
        print(n)


if __name__ == "__main__":
    main()
