def func(a):
    return a**2


def main():
    numbers = [1, 2, 3, 4, 5]
    result = list(map(func, numbers))
    print(result)

    result = list(map(lambda a: a**2, numbers))
    print(result)

    result = [n**2 for n in numbers]
    print(result)


if __name__ == '__main__':
    main()
