code: private function writeBorderPr(XMLWriter $objWriter, $pName, Border $pBorder)
      {
          // Write BorderPr
          if ($pBorder->getBorderStyle() != Border::BORDER_NONE) {
              $objWriter->startElement($pName);
              $objWriter->writeAttribute('style', $pBorder->getBorderStyle());
  
              // color
              $objWriter->startElement('color');
              $objWriter->writeAttribute('rgb', $pBorder->getColor()->getARGB());
              $objWriter->endElement();
  
              $objWriter->endElement();
          }
      }
docs: Write BorderPr.
  
  @param XMLWriter $objWriter XML Writer
  @param string $pName Element name
  @param Border $pBorder Border style