ifNothing :: Maybe a -> Maybe a -> Maybe a
ifNothing mbX mbY = case mbX of
  Nothing  -> mbY
  _        -> mbX
ifNothing :: Maybe a -> Maybe a -> Maybe a
ifNothing mbX mbY = case mbX of
  Nothing  -> mbY
  _        -> mbX
ifNothing mbX mbY = case mbX of
  Nothing  -> mbY
  _        -> mbX