Defining “boolness” of a class in python

Question

Why doesn\'t this work as one may have naively expected?

class Foo(object):
    def __init__(self):
        self.bar = 3
    def __bool__(self):
        retu         


        

Answer 1

Because the corresponding special method is called __nonzero__() in Python 2, and not __bool__() until Python 3.