convertKeysInMap
    :: forall k k' v
     . Ord k => Ord k'
    => (k -> k')
    -> (Map k v)
    -> (Map k' v)
convertKeysInMap toNewKey srcMap =
    foldr foldingF Map.empty $ Map.keys srcMap
    where
        foldingF oldKey resMap =
            maybe 
                resMap 
                (\v -> Map.insert (toNewKey oldKey) v resMap)
                $ Map.lookup oldKey srcMap

mapKeys :: forall k k' v. Ord k => Ord k' => (k -> k') -> Map k v -> Map k' v
mapKeys f = fromFoldable <<< amap (lmap f) <<< toUnfoldable where
  amap :: forall a b. (a -> b) -> (Array a -> Array b)
  amap = map