protected function getDateTime($dateTime)
    {
        if ($dateTime instanceof \DateTime) {
            return $dateTime;
        }

        if ((is_string($dateTime) && (int) $dateTime > 0) || is_numeric($dateTime)) {
            return (new \DateTime())->setTimestamp($dateTime);

        }

        throw new \common_Exception(__('A date has to be a Datetime or timestamp'));
    }