[d23]

That line and this one lead me to believe he's full of hot air:

> if a method does not use the object's state (no `self` usage) make it a `class-` or `staticmethod`.

Uh, that's a little too "cookbook" for my tastes. The decision of whether to make something a class / static method or not should be decided based on what the function is doing, rather than some pointless dogma. I'm assuming he means this method:

> def alarm(self): > with open(BUZZER_MP3_FILE) as f: > play_sound(f.read())

It's a design decision, and one that is particularly trivial at that. Let's say the effects an alarm ultimately change, resulting in an internal state read / write on the object. Now you have to go back and update the class despite the fact that it at a higher philosophical level one could argue that an alarm should only be triggered on an individual boiler.

Point being: it's nit-pickery for nit-pickery's sake. I don't personally use `return None`, but it's certainly more explicit and is fine to use if your judgment has found it to make sense.