A few useful tips

When writing functions, it is very useful to follow guidelines so that you write them well. We will quickly point some of them out:

• Functions should do one thing: Functions that do one thing are easy to describe in one short sentence; functions that do multiple things can be split into smaller functions that do one thing. These smaller functions are usually easier to read and understand.
• Functions should be small: The smaller they are, the easier it is to test and write them so that they do one thing.
• The fewer input parameters, the better: Functions that take a lot of parameters quickly become hard to manage (among other issues).
• Functions should be consistent in their return values: Returning False and returning None are not the same thing, even if, within a Boolean context, they both evaluate to False. False means that we have information (False), while None means that there is no information. Try writing functions that return in a...