Special methods

Methods wrapped in double underscores, like __init__, are special methods (people call them dunder methods). Python calls them for you: __str__ when you print an object, __repr__ for a developer view, __eq__ for ==, __add__ for + and __len__ for len(). Defining them makes your objects feel built in.

How it reads

• a + b really calls a.__add__(b)
• Without __eq__, == only checks whether two names point at the same object
• __str__ decides what print shows

Cloud tip: Define __repr__ too: it is what you see for objects inside lists and in error messages.