map -package:containers -package:bytestring -package:foldl -package:charset -is:exact -package:monoidal-containers -package:os-string -package:amazonka-core -package:conduit -package:incipit-base -package:base-compat package:pipes is:exact

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

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