description

# insert method Null safety

void insert (

1. int index,
2. E element

)

Inserts the object at position `index` in this list.

This increases the length of the list by one and shifts all objects at or after the index towards the end of the list.

The list must be growable. The `index` value must be non-negative and no greater than length.

## Implementation

    void insert(int index, E element);