public function insertNewRowBefore($pBefore, $pNumRows = 1)
    {
        if ($pBefore >= 1) {
            $objReferenceHelper = ReferenceHelper::getInstance();
            $objReferenceHelper->insertNewBefore('A' . $pBefore, 0, $pNumRows, $this);
        } else {
            throw new Exception('Rows can only be inserted before at least row 1.');
        }

        return $this;
    }