I usually find that novices do not want to learn how to write function. The main argument is that their code just works, so why learn a new concept?
They have a good argument there. In order to introduce functions we to overcome that prejudice by:
- teaching all the advantages that a function brings over a plain script/code block;
- show that functions are not a hard concept to grasp.
The lesson on python functions does (1) well, and the simple concept map below might help with (2).