How does this code works:

[vch]

Here's an example from some book:

def foo(n):
        s = [n]
        def bar(i):
                s[0] += i
                return s[0]
        return bar

what I don't understand is how this example works, taking into account 
the LGB rule. I thought that s is not accessible from bar, but it is, 
apparently. Why?
-- 
http://mail.python.org/mailman/listinfo/python-list