Unbound Local error? How?

[Hari Sekhon]

I've got some code as follows:

import re
re_regexname = re.compile('abc')

.....
..... various function defs
.....

def func1():
    ...
    func2()
    ...

def func2():
    if re_regexname.match('abc'):
       <do something>

if __name__ == '__main__':
    func1()


but this returns the Traceback:

UnboundLocalError: local variable 're_regexname' referenced before 
assignment


How?

It was declared in the zero level indentation near the top of the 
script! I don't understand this, isn't a function supposed to be able to 
reference stuff in the containing function or the top level?