code: private function writeCellSpan(XMLWriter $objWriter, $curColumn, $prevColumn)
      {
          $diff = $curColumn - $prevColumn - 1;
          if (1 === $diff) {
              $objWriter->writeElement('table:table-cell');
          } elseif ($diff > 1) {
              $objWriter->startElement('table:table-cell');
              $objWriter->writeAttribute('table:number-columns-repeated', $diff);
              $objWriter->endElement();
          }
      }
docs: Write span.
  
  @param XMLWriter $objWriter
  @param int $curColumn
  @param int $prevColumn