part' :: [MediaType] -> Maybe Int
part' (x:xs) = case x of
    (Part a) -> Just a
    _ -> part' xs
part' :: [MediaType] -> Maybe Int
part' (x:xs) = case x of
    (Part a) -> Just a
    _ -> part' xs
part' (x:xs) = case x of
    (Part a) -> Just a
    _ -> part' xs