[Tutor] Acting on objects in a list - how to make the change permanent?

[Adam Cripps]

My python project (http://savannah.nongnu.org/projects/newmag) is
teaching me a fair bit about how to write python code. However, I'm
still a long way away from being remotely good, as some of my recent
posts have shown.

I'm working on deleting instance objects and I've created a list of
objects which is then piped through a menu to allow the user to choose
which one is deleted.

The basic structure of the code is this: 

 * choose_what_to_edit  - creates a list which calls return_object_list
     * return_object_list - return_object_list  -chooses what level
the user wants to select an object
        * choosetitle - selects a title
            * chooseissue - if necssary selects an issue from the selected title
               * choosearticle - and if nescessary, selects an article
from the selected issue.

Basically, from this code, I get a list, which has objects within it.
If I alter the objects within this list, how do I make them permanent?
I'm currently trying to delete an item/object of the list the command
del returned_list[choice] - however, this doesn't seem to be a
permanent change. For the full code listing, please see the CVS
project page.

Am I right in thinking that the list of objects will be referenced
through to the actual instances, and if so, why aren't they being
deleted? I've read some of the python docs, but can't see the solution
here and would appreciate a more informed/specialised approach.

TIA.
Adam