pt :: [Direction a] -> Hash -> Branch a -> ([Direction a], Maybe a)
pt path h (Twig h' a) = if h == h' then (path, Just $ packet a) else noAns
pt :: [Direction a] -> Hash -> Branch a -> ([Direction a], Maybe a)
pt path h (Twig h' a) = if h == h' then (path, Just $ packet a) else noAns
pt path h (Twig h' a) = if h == h' then (path, Just $ packet a) else noAns