Anatomy

A function in Python uses the def keyword to tell Python you are writing a function and indentation is used to define the code block that will be run.

In parenthesis (), parameters can be passed to the function.

The name of the function uses snake_case and the parenthesis indicate that this is a function. Take a look at PEP8.

As with loops, the colon denotes the start of a block.

We include a docstring (between """ marks) to explain the function.

def name_of_function():
    """
    Simple test function
    """
    print("Yoo hoo!")

If I run this, nothing happens. I have created a function, but I have not called the function. I add the following line underneath, with no indentation and rerun.

name_of_function()

This final line calls the function.

Try doing this without the brackets.

What happens and why?