stripPrefixBS :: ByteString -> ByteString -> Maybe ByteString
stripPrefixBS x y
    | x `S.isPrefixOf` y = Just $ S.drop (S.length x) y
    | otherwise = Nothing
stripPrefixBS :: ByteString -> ByteString -> Maybe ByteString
stripPrefixBS x y
    | x `S.isPrefixOf` y = Just $ S.drop (S.length x) y
    | otherwise = Nothing
stripPrefixBS x y
    | x `S.isPrefixOf` y = Just $ S.drop (S.length x) y
    | otherwise = Nothing