Uploadcare\Api::dateTimeString PHP Method

    public static function dateTimeString($datetime)
    {
        if ($datetime === null) {
            return null;
        }
        if (is_object($datetime) && !$datetime instanceof \DateTime) {
            throw new \Exception('Only \\DateTime objects allowed');
        }
        if (is_string($datetime)) {
            $datetime = new \DateTime($datetime);
        }
        return $datetime->format(\DateTime::ATOM);
    }