public function hasSharedStrings()
    {
        $hasSharedStrings = false;
        $zip = new \ZipArchive();

        if ($zip->open($this->filePath) === true) {
            $hasSharedStrings = ($zip->locateName(self::SHARED_STRINGS_XML_FILE_PATH) !== false);
            $zip->close();
        }

        return $hasSharedStrings;
    }