>>725

>>> def fa():
... a=3
... def fb():
... a+=5
... print a
... print a
... return fb
...
>>> b=fa()
3
>>> b()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 4, in fb
UnboundLocalError: local variable 'a' referenced before assignment
>>>