map -package:containers -package:Cabal-syntax -package:insert-ordered-containers -package:monoidal-containers -package:base-prelude -package:base-compat -package:blaze-html -package:aeson -is:exact -package:case-insensitive -package:incipit-base is:exact package:basement
Map all element a from a block to a new block of b
Map all elements in a list