name space problem

[BBands]

An example:

class classA:
    def __init__(self):
        self.b = 1

def doStuff():
    some calcs
    a..b = 0

a = classA():
print a.b
doStuff()
print a.b

That works as hoped, printing 1, 0.

But, if I move doStuff to another module and:

import doStuff

class classA:
    def __init__(self):
        self.b = 1

a = classA()
print a.b
doStuff.doStuff()
print a.b

I get a 1 printed and an error: NameError: global name 'a' is not
defined

I think this is a name space issue, but I can't grok it.

Thanks in advance,

     jab