public function getCellByColumnAndRow($columnIndex, $row, $createIfNotExists = true)
    {
        $columnLetter = Coordinate::stringFromColumnIndex($columnIndex);
        $coordinate = $columnLetter . $row;

        if ($this->cellCollection->has($coordinate)) {
            return $this->cellCollection->get($coordinate);
        }

        // Create new cell object, if required
        return $createIfNotExists ? $this->createNewCell($coordinate) : null;
    }