$4.$ Define doubly linked list? Write an algorithm to perform the following operations on the doubly

linked list.

$$ Insertion $$ Adds an element at the beginning of the list.

$$ Deletion $$ Deletes an element at the beginning of the list.

$$ Insert After $$ Adds an element after an item of the list.

$$Delete Last $$ Deletes an element from the end of the list.

$$ Delete $$ Deletes an element from the list using the key.