This code or a variant of this code is common in many of the methods in the Linked List. What does this code do and what is its speed in Big O notation?

while temp next next $!=$ None:

temp $=$ temp.next

Here is another version

for $i$ in range$($index $-1)$:

if temp next $!=$ None:

temp $=$ temp.next

Traverses the linked list nodes. The speed is $O(n).$

It adds an item to the linked list. Its speed is $O(n).$

It displays the list elements.

It adds an item to the linked list. Its speed is $O(1).$