map is:exact -package:charset -package:basement -package:containers -package:bytestring -package:os-string -package:psqueues -package:conduit -package:invertible -package:filepath package:unordered-containers

Transform this map by applying a function to every value.
Transform this set by applying a function to every value. The resulting set may be smaller than the source.
>>> HashSet.map show (HashSet.fromList [1,2,3])
HashSet.fromList ["1","2","3"]