super() in __init__

Question

super() in __init__

Accepted Answer

When a subclass defines its own __init__, it must explicitly call super().__init__() if it wants the parent class to initialize its attributes. super().__init__(color) runs Shape.__init__ on the Square instance, which sets self.color = 'red'. Then self.side = 4 adds the subclass-specific attribute. Forgetting the super().__init__() call is a common mistake - the instance would be missing self.color and any subsequent access would raise AttributeError.