protected function folder($output, array $uris)
    {
        $folder = (string) '';

        foreach ((array) $uris as $uri) {
            $directory = $output . '/' . (string) $folder;

            file_exists($directory) ?: mkdir($directory);

            $folder === $uri ?: $folder .= '/' . $uri;
        }

        return $folder;
    }