codec' :: [MediaType] -> Maybe CodecDer
codec' (x:xs) = case x of
    (Codec a) -> Just a
    _ -> codec' xs
codec' :: [MediaType] -> Maybe CodecDer
codec' (x:xs) = case x of
    (Codec a) -> Just a
    _ -> codec' xs
codec' (x:xs) = case x of
    (Codec a) -> Just a
    _ -> codec' xs