$($Python$)$ Define a function named insert that inserts an item into a singly linked structure at a given position. The function expects three arguments: the item, the position, and the linked structure. $($The latter may be empty.$)$ The function returns the modified linked structure. If the position is greater than or equal to the structure$$s length, the function inserts the item at its end. An example call of the function, where head is a variable that either is an empty link or refers to the first node of a structure, is head $=$ insert$(1,$ data, head$).$

def insert$($index$,$ newItem, head$)$: