private function isValidSpecialPrice(SpecialPrice $specialPrice)
    {
        $startDate = $specialPrice->getStartDate();
        $endDate = $specialPrice->getEndDate();
        $now = new \DateTime();

        // Check if special price is stil valid.
        if (($now >= $startDate && $now <= $endDate) ||
            ($now >= $startDate && empty($endDate)) ||
            (empty($startDate) && empty($endDate))
        ) {
            return true;
        }

        return false;
    }