There's no attempt to Pythonify or make Objective C like the low level runtime supporting classes to make them Pythonic. And how you have these named, these really oddly named methods and then variables,. right, like you can't just say string lower, you've got to get like a weird set of incantations to sort of invoke a lower case type of behavior. So what this is doing is think of it as every time you see an underscore in a pi objective C method call, you need to have a variable you didn't have an argument to that method call.