\section[Bags]{@Bag@: an unordered collection with duplicates}
\begin{code}
+#include "HsVersions.h"
+
module Bag (
Bag, -- abstract type
) where
#ifdef COMPILING_GHC
-import Ubiq{-uitous-}
+IMP_Ubiq(){-uitous-}
+IMPORT_1_3(List(partition))
import Outputable ( interpp'SP )
import Pretty