When to decide whether or not to have an argument in a class method?

[buran]

you have a class House. it has properties - side, roof, volume.
i.e. self.side is a property. self.volume() is also a property (method to be precise). there is no such property self.side.volume().
self.side is actually just a floating number (i.e. float object, not House object). you need to read/revisit class basics. https://python-forum.io/Thread-Classes-Class-Basics