Create an insert before method for a doubly linked list in c. The method, insertBefore(*List, *ListNode, int) will take a LinkedList, and node to be inserted, and a key value to determine where the node should be inserted. If the list has a node that contains that key, insert before that node. if the list does not contain a node with that value, that node is the new head of the list. The first and last node values must change accordingly in the *List pointer with every insert where appropriate.

typedef struct ListNode { struct ListNode *next; struct ListNode *prev; int value; } ListNode;

typedef struct List { int count; ListNode *first; ListNode *last; } List;