code: 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();
      }
docs: Write WorkbookPr.
  
  @param XMLWriter $objWriter XML Writer