public function getWorksheetsCount()
    {
        //build URI to merge Docs
        $strURI = Product::$baseProductUri . '/cells/' . $this->getFileName() . '/worksheets';
        //sign URI
        $signedURI = Utils::sign($strURI);
        $responseStream = Utils::processCommand($signedURI, 'GET', '', '');
        $json = json_decode($responseStream);
        return count($json->Worksheets->WorksheetList);

    }