def my_function():
    print("Hello World!")



my_function()


def add_two_numbers(x1, x2):
    total = x1 + x2
    return total

y = add_two_numbers(3,5)
print(y)


def print_argument(x=5):
    print(x)


print_argument()
print_argument(3.)
print_argument(x=3.)


def multiply_by_7(x=1):
    if x == 6:
        print("The Answer to the Ultimate Question of Life, "
              "the Universe and Everything.")
    else:
        print(x*7)

multiply_by_7()
multiply_by_7(4)
multiply_by_7(6)


def slicer(seq, start=None, stop=None, step=None):
    """ Implement basic Python slicing."""
    return seq[start:stop:step]
l = [1, 2, 3, 4, 5, 6]
slicer()
slicer(l)
slicer(l, stop=2)
slicer(l, stop=5, step=2)


def funcname(params):
    """Concise one-line sentence describing the function.

    Extended summary which can contain multiple paragraphs.
    """
    # function body
    pass