extraneous import statements needed

[Jeff Davis]

I created a module that is essentially one big class. At the top I have a 
group of import statements (outside the class). Within my methods I call 
functions such as string.split(). However, I get strage error messages 
about "type None does not have attribute split" or something similar 
(always thinks that the module name is instead a None object). 

However, this behavious does not seem consistant. I tried to narrow down 
the cause of the failure, but all of the text cases I tried worked as I 
expected (calling the split function of the string module that I imported 
outside the class). 

I can fix it easily by just adding imports at the top of my class methods 
until I don't get any more errors, but that doesn't help me understand 
what's wrong.

Has anyone had a similar problem? I suppose it's a scoping issue, but 
wouldn't I just get a NameError exception? How does it get set to None? 
Did the outer import fail somehow maybe?

Sorry I didn't include an example, but as I said it seemed inconsistant 
and I have not (yet) been able to narrow down the cause or a good 
example/test case. Since my methods are mostly dependent on eachother, it 
is difficult to remove select parts without encountering an unrelated 
error.

Thanks,
        Jeff