nixpkgs/pkgs/development/libraries/haskell/multiset/default.nix

{cabal}:

cabal.mkDerivation (self : {
  pname = "multiset";
  version = "0.2";
  sha256 = "35d76c026bab0dbdf761c8590297d718507bb9ef93c30bce4f524efee23f5323";
  meta = {
    description = "A variation of Data.Set. Multisets, sometimes also called bags, can contain multiple copies of the same key";
  };
})