You only need to submit the Python source code file, but as the example in the chapter shows, you should be designing and building your software by:

1. starting with notes,
2. turning those notes into comments within the code,
3. then writing the code to do what the comments say to do.

It is a good design process that will help you to manage the growing complexity of the software we are developing. It helps to separate the logical development of the algorithm from the language of creating the source code.

Your finished program should then be well-documented and exhibit good modular design.