public function setDateTime(DateTimeInterface $dt)
    {
        $tz = $dt->getTimeZone();
        $isUtc = in_array($tz->getName(), ['UTC', 'GMT', 'Z']);

        if ($isUtc) {
            $value = $dt->format('Ymd\\THis\\Z');
        } else {
            // Calculating the offset.
            $value = $dt->format('Ymd\\THisO');
        }

        $this->value = $value;
    }