# test that __getattr__ and instance members don't override builtins class C: def __init__(self): self.__add__ = lambda: print('member __add__') def __add__(self, x): print('__add__') def __getattr__(self, attr): print('__getattr__', attr) return None c = C() c.add # should call __getattr__ c.__add__() # should load __add__ instance directly c + 1 # should call __add__ method directly