It's true that people tend to force OOP onto python, especially when coming from other languages. But I think it's good to mention that in certain cases, keeping state by building a class is necessary, or at least easier than using a module-based approach.

  > The double checking costs a few CPU cycles but saves a lot of keystrokes.

Not sure I agree with this, idiomatic python should be explicit, even if it means more keystrokes.