gistfile1.py

>>> b = 0
>>> def incB():
...   b += 1
... 
>>> c = []
>>> def addC():
...   c.append(1)
... 
>>> b
0
>>> c
[]
>>> incB()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in incB
UnboundLocalError: local variable 'b' referenced before assignment
>>> addC()
>>> c
[1]

Heh I wouldn't mind that either since I absolutely hate globals in code that are not constants declared in ALL_CAPS. I really doubt that'd fly if suggested on python-ideas@ though. ;)