public function setBorderForCellRange(
        PHPRtfLite_Border $border,
        $startRow,
        $startColumn,
        $endRow = null,
        $endColumn = null
    ) {
        list($startRow, $startColumn, $endRow, $endColumn)
                = PHPRtfLite_Table::getValidCellRange($startRow, $startColumn, $endRow, $endColumn);

        if ($this->checkIfCellExists($startRow, $startColumn)
            && $this->checkIfCellExists($endRow, $endColumn))
        {
            $cells = $this->getCellsByCellRange($startRow, $startColumn, $endRow, $endColumn);
            foreach ($cells as $cell) {
                $cell->setBorder(clone($border));
            }
        }
    }