[Tutor] how to do a (special) sorted list

[Adam Groszer]

Dear all,

As I wrote in 'implementing relationship between objects' I'm trying to move
from relational data storage to object oriented.

The second problem is to implement a sorted list with the following options:

1. The items should not be 'unique' as they are with a dict or ZODB.BTree.
2. Items should be accessible with the key (this is really simple)
3. Items should be accessible with a sequence number
4. After <3> is working it's easy to implement a 'first', 'last', 'next',
'prev' method to walk the list

Is there maybe any module or package to accomplish this?

Thanx,

Adam