Very well said! Thank you :) As you may have seen from the description, this is a question from a book, Starting out with Python that only allows you to include knowledge and concept from a particular chapter. The author certainly knows there's a predefined max function. But as a "programming challenge" and a learning process, the author was explicit and wanted us to first create the max function or at least a variation of it, to see how it works first and to see the inner working of it instead of just relying on it. This was a test, so students can appreciate predefined functions even better by first understanding the concept of creating functions.
I understand programmers wouldn't normally do that and I 100% agree :) If I was creating a program for production, I would use the predefined max() but again this was only to recreate the wheel, not for a bad purpose but for learning purposes. You're right! I should at least point out in the description, there's a predefined function max() ( Done! :) see description ), for those who don't know, but the students using the book definitely would know about it if they read the book.
Thank you so much 
RE: 5.12 Maximum of Two Values - Python