map -package:containers -package:bytestring -package:invertible -package:basement -package:base -package:charset -package:imports -package:conduit -package:blaze-html -package:pipes package:hedgehog is:exact
Generates a map using a
Range to determine the length.
This may fail to generate anything if the keys produced by the
generator do not account for a large enough number of unique
items to satify the required map size.