public function filter($value = [])
    {
        $sum = 0;
        $amount = 0;
        $absoluteDiscount = 0;
        if (empty($value)) {
            return 0;
        }

        foreach ($value as $channelKey) {
            /* @var $channel ChannelOptions */
            $channel = $this->providers->getChannel($channelKey);
            if ('yawik' == $channelKey) {
                $absoluteDiscount = 100;
            }
            if ($channel instanceof ChannelOptions && $channel->getPrice('base')>0) {
                $sum += $channel->getPrice('base');
                $amount++;
            }
        }
        $discount=1-($amount-1)*13.5/100;
        if ($discount>0) {
            $sum= round($sum * $discount, 2);
        }
        return $sum-$absoluteDiscount;
    }