public function getCell($rowIndex, $columnIndex)
    {
        if ($this->checkIfCellExists($rowIndex, $columnIndex)) {
            return $this->getRow($rowIndex)->getCellByIndex($columnIndex);
        }

        throw new PHPRtfLite_Exception('Wrong index for cell! You gave me: (row:' . $rowIndex . ', column:' . $columnIndex . ')');
    }