Question

Some legacy code I’m working with that works [code replaced by problem-reproducing code]:

class foo:
    pass

class bar(foo):
    def __new__(cls):
        global BIZ
        if BIZ is not None:
            pass

bar()

but when I change it to

class foo(object):

then python prints:

Traceback (most recent call last):
  File "test.py", line 11, in <module>
    bar()
  File "test.py", line 8, in __new__
    if BIZ is not None:
NameError: global name 'BIZ' is not defined

Why is this?

Answer 1

The __new__ special method only applies to new-style classes (those inheriting directly or indirectly from object). Without subclassing object your code isn’t getting called.