private function createZip($pFilename)
    {
        // Create new ZIP file and open it for writing
        $zip = new ZipArchive();

        if (file_exists($pFilename)) {
            unlink($pFilename);
        }
        // Try opening the ZIP file
        if ($zip->open($pFilename, ZipArchive::OVERWRITE) !== true) {
            if ($zip->open($pFilename, ZipArchive::CREATE) !== true) {
                throw new WriterException("Could not open $pFilename for writing.");
            }
        }

        return $zip;
    }