split0 :: IntMap a -> (WordMap_ W.L a, WordMap_ W.L a)
split0 (IntMap (WordMap Empty)) = (Empty, Empty)
split0 :: IntMap a -> (WordMap_ W.L a, WordMap_ W.L a)
split0 (IntMap (WordMap Empty)) = (Empty, Empty)
split0 (IntMap (WordMap Empty)) = (Empty, Empty)