map -package:amazonka-core -package:conduit -is:exact -package:dlist -package:basement -package:case-insensitive -package:base -package:hedgehog -package:charset -package:imports -package:os-string -package:filepath -package:monoidal-containers is:exact package:pipes

Apply a function to all values flowing downstream
map id = cat

map (g . f) = map f >-> map g