See http://docs.python.org/lib/os-file-dir.html 
Python Library Reference, first example in Section
6.1.4 Files and Directories has an obvious syntax error.

import os
from os.path import join, getsize
for root, dirs, files in os.walk('python/Lib/email'):
    print root, "consumes",
    print sum(getsize(join(root, name)) for name in
files),  #error
    print "bytes in", len(files), "non-directory files"
    if 'CVS' in dirs:
        dirs.remove('CVS')  # don't visit CVS directories


Should be     
    print sum([getsize(join(root, name)) for name in
files]),   

Logged In: YES 
user_id=1188172

No, sorry. The docs you are referring to are the docs for
Python 2.4, and Python 2.4 introduces so-called "generator
expressions", and this is one.

See http://docs.python.org/whatsnew/node4.html for more
information.