This a small part of my assignment. This is linked List. I watched so many videos on linked lists, but I can not understand how to do __getitem__,__setitem__, and the __delitem__ functions. I keep getting it all wrong. This is Python.

Overview For this assignment you will complete the implementation of the linked list data structure ( LinkedList) started during class, so that it supports (nearly) all the common and mutable sequence operations. Your implementation should make use of doubly-linked nodes (i.e., each containing a prior and next reference), an ever-present sentinel head node, and a circular" topology (where the head and last nodes are, logically, neighbors). This setup should substantially simplify your implementation by reducing the edge cases and amount of iteration you have to perform. Your implementation should not make use of the built-in Python list data structure (finally!) Implementation Details LinkedList As with the previous assignment, we've partitioned the LinkedList methods you need to implement (and the test cases that follow) into seven categories 1. Subscript-based access 2. Stringification 3. Single-element manipulation 4. Predicates (True/False queries) 5. Queries 6. Bulk operations 7. Iteration