private function isActive(CouponInterface $coupon, \DateTime $now = null)
    {
        if (!$coupon->isEnabled()) {
            return false;
        }

        $now = $now ?: $this
            ->dateTimeFactory
            ->create();

        if ($coupon->getValidFrom() > $now) {
            return false;
        }

        $validTo = $coupon->getValidTo();
        if ($validTo && $now > $validTo) {
            return false;
        }

        return true;
    }