Module review:

* Changed variable name from 'list' to 'flist'.
* Replaced "while 1" with "while True".
* Replaced if/elif/elif/elif structure with a shorter and
  faster dispatch dictionary that maps attrs to methods.
* Simplified and sped comparison logic by using
  ifilter, ifilterfalse, and dict.fromkeys.
* Used True and False rather than 1 and 0.