Functions are just like procedures but with one key difference that makes them even more useful.
This tutorial guides you through what a function is, how to use them and how and when you should define your own functions.
Page 1: Intro
Page 2: The theory: learn what you need to know as fast as possible.
Page 3: Try it: try out and adapt some working python code snippets.
Page 4: Debug it: Learn how to find and fix common mistakes.
Page 5: Extend it: Choose a project idea to use your newfound python skills.