# Pastebin IV3jl2bc
λ> :t got
got :: Either String (Header, V.Vector a)
λ> :t convert
convert :: a -> (k, v)
λ> :t fmap (Map.fromList . toList . fmap convert)
fmap (Map.fromList . toList . fmap convert)
  :: (Ord k, Foldable t, Functor f, Functor t) =>
     f (t a1) -> f (Map k a2)