Elgg\Notifications\SubscriptionsService::addSubscription PHP Метод

    public function addSubscription($userGuid, $method, $targetGuid)
    {
        if (!in_array($method, $this->methods)) {
            return false;
        }
        $prefix = self::RELATIONSHIP_PREFIX;
        return add_entity_relationship($userGuid, "{$prefix}{$method}", $targetGuid);
    }