cssURLs :: MediaBag -> Maybe String -> FilePath -> ByteString
        -> IO ByteString
cssURLs media sourceURL d orig = do
  res <- runParserT (parseCSSUrls media sourceURL d) () "css" orig
  case res of
       Left e    -> warn ("Could not parse CSS: " ++ show e) >> return orig
       Right bs  -> return bs
cssURLs :: MediaBag -> Maybe String -> FilePath -> ByteString
        -> IO ByteString
cssURLs media sourceURL d orig = do
  res <- runParserT (parseCSSUrls media sourceURL d) () "css" orig
  case res of
       Left e    -> warn ("Could not parse CSS: " ++ show e) >> return orig
       Right bs  -> return bs
cssURLs media sourceURL d orig = do
  res <- runParserT (parseCSSUrls media sourceURL d) () "css" orig
  case res of
       Left e    -> warn ("Could not parse CSS: " ++ show e) >> return orig
       Right bs  -> return bs