private function writePrintOptions(XMLWriter $objWriter, PhpspreadsheetWorksheet $pSheet)
    {
        // printOptions
        $objWriter->startElement('printOptions');

        $objWriter->writeAttribute('gridLines', ($pSheet->getPrintGridlines() ? 'true' : 'false'));
        $objWriter->writeAttribute('gridLinesSet', 'true');

        if ($pSheet->getPageSetup()->getHorizontalCentered()) {
            $objWriter->writeAttribute('horizontalCentered', 'true');
        }

        if ($pSheet->getPageSetup()->getVerticalCentered()) {
            $objWriter->writeAttribute('verticalCentered', 'true');
        }

        $objWriter->endElement();
    }