fromVV :: forall a m n. ( ) => V m (V n a) -> M m n a
fromVV vv = M $ P.foldr ((V.++) . toVector) V.empty vv
fromVV :: forall a m n. ( ) => V m (V n a) -> M m n a
fromVV vv = M $ P.foldr ((V.++) . toVector) V.empty vv
fromVV vv = M $ P.foldr ((V.++) . toVector) V.empty vv