Inserts into the receiver the characters of a given string at a given location.
- iOS 2.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
The string to insert into the receiver.
amust not be
The location at which
ais inserted. The location must not exceed the bounds of the receiver.
The new characters begin at
an and the existing characters from
an to the end are shifted by the length of
This method treats the length of the string as a valid index value that returns an empty string.