Globals in nested functions

[jm.suresh@no.spam.gmail.com]

def f():
    a = 12
    def g():
        global a
        if a < 14:
            a=13
    g()
    return a

print f()

This function raises an error. Is there any way to access the a in f()
from inside g().

I could find few past discussions on this subject, I could not find
the simple answer whether it is possible to do this reference.

-
Suresh