map -package:containers -package:base-compat -package:aeson is:exact -package:dlist -package:Cabal-syntax -package:base-prelude -package:case-insensitive -package:monoidal-containers -package:base-compat-batteries -package:bytestring -package:ghc package:basement
Map all element a from a block to a new block of b
Map all elements in a list