Why is a() + b() translated to b.__radd__(a())

Question

This is from the magic methods lesson question 2. I keep thinking the add function/method is a part of a when you call it, so it should be a.__radd__(b()) right?

Answer 1

a() + b() is translated to a.__add__(b()).

__radd__ is "reverse add". The lesson says that if __add__ hasn't been defined, it will look for __radd__ and translate a() + b() to b.__radd__(a()).