private function writeWorkbookPr(XMLWriter $objWriter)
    {
        $objWriter->startElement('workbookPr');

        if (Date::getExcelCalendar() == Date::CALENDAR_MAC_1904) {
            $objWriter->writeAttribute('date1904', '1');
        }

        $objWriter->writeAttribute('codeName', 'ThisWorkbook');

        $objWriter->endElement();
    }