[Tutor] Sorting a list of objects on different fields

[Terry Carroll]

I have a list (or a list-like object, doesn't matter) of objects, each of
which has multiple fields.  I want to be able to arbitrarily sort the list
on any of them, or at least on several of them.

To make this a little more concrete, here's a simplified idea.  Say the 
objects each represent a file, and I've got fields in it 
like this:

 self.filesz: size of the file
 self.filename: name of the file
 self.users : a list of people who need to know if the file gets updated
 self.filetype : a short description of the file contents

 etc.


I sometimes want to sort the list by filesz; and sometimes by filename; 
and maybe sometimes by some other field.

My sense right now is that the "list" of these objects itself should be an 
object inheriting from list, and that I should create a small sort method 
for each field I intend to sort on.  (I don't have the book handy, but 
there's a nice recipe for this in the Python Cookbook, 2d Edition, for 
such a method.)

Is there a better (more clear and easy) way to be able to do this, or 
am I pretty much on the right track?