public function filter(EventInterface $event)
    {
        if (!$event instanceof UserEventInterface) {
            return null;
        }

        $channels = $this->getChannels($event);
        if (empty($channels)) {
            return null;
        }

        $commonChannels = array_intersect($channels, $this->channels);
        if ($commonChannels) {
            return true;
        }

        return false;
    }