Inserts all objects of [iterable] at position [index] in this list.
Inserts all objects of [iterable] at position [index] in this list.
This increases the length of the list by the length of [iterable] and shifts all later objects towards the end of the list.
An error occurs if the [index] is less than 0 or greater than length. An [UnsupportedError] occurs if the list is fixed-length.