What is UnboundLocalError for?

[Alex]

Tee hee.  I'll get control over that pesky mouse one of these days.

This is what I meant to paste in:

>>> def f(): l = l + 1
... 
>>> f()
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "<stdin>", line 1, in f
UnboundLocalError: l
>>> 

Thanks for the replies.  Good guess, Tim.

Alex.