bz2 module

[Brad Tilley]

I'm having a bit of trouble using the bz2 module. The documentation for 
it is very poor. Here's what I'm trying to do:

import bz2

x = file('test.bkf', 'rb')

while True:
         data = x.read(1024000)
         if not data:
                 break
         bz2.BZ2File('test.bkf.copy', 'w').write(data)

x.close()

It fails with this error:
AttributeError: 'module' object has no attribute 'BZ2File'

Can anyone give me an example of how to use bz2 to compress files. Why 
don't the docs give examples of this?!?

Thanks,
Brad