public function generateRokkaUrl(
      $hash,
      $stack,
      $format = 'jpg',
      $seo = null,
      $seoLanguage = 'de'
    ) {
        if (null === $format) {
            $format = 'jpg';
        }
        $slug = null;
        if (!empty($seo) && null !== $seo) {
            if (null === $seoLanguage) {
                $seoLanguage = 'de';
            }
            $slug = self::slugify($seo, $seoLanguage);
        }
        $path = UriHelper::composeUri(['stack' => $stack, 'hash' => $hash, 'format' => $format, 'filename' => $slug]);

        return $this->rokkaDomain.$path->getPath();
    }