public function isZip(UploadedFile $file, $workspace)
    {
        $isZip = false;
        if ('application/zip' === $file->getClientMimeType() || true === $this->getZip()->open($file)) {
            // Correct Zip type => check if html root file exists
            $rootFile = $this->guessRootFile($file, $workspace);

            if (!empty($rootFile)) {
                $isZip = true;
            }
        }

        return $isZip;
    }