public function lastModified($row, $column):?\DateTime
    {
        $file = $this->getData($row, $column);

        if ($file == null) {
            return null;
        }

        $file = rtrim($file, DIRECTORY_SEPARATOR);
        $file = $this->rootPath . DIRECTORY_SEPARATOR . $file;

        $format = "YmdHis";

        $dateTime = \DateTime::createFromFormat($format, date($format, filemtime($file)));

        return $dateTime;
    }