You must not have looked at linked list. Besides being non-pythonic and having get and set functions, they don't even consistently use them.

Then there's the bug that you can't delete the first node in a list.

And then there's the fact that double linked list doesn't have a tail pointer.

And then there's the fact that they use the same node class in double linked as single, but the previous member is set by the list, but isn't always set so you might get an exception some times.

Then there's the fact that search is only implemented for single linked .. Oh and its RECURSIVE!

It'd be one thing if this was just them showing how they learned something in a blog post... But this was meant for teaching.... And yet there's no description and clearly obvious bugs.