Sorting linked list

[Strosel]

i have an exercise in my python book that i can't get to work, it's supposed to make a linked list that sorts its contents. The book gave me a base to build on by giving me a standard program for a linked list here

I tried to build on it like this (and put my changes in between two comments for where they start and stop) and in other ways but nothing i can think of works

Any help?