private function buildBlacklistedNodes(ResultCollection $result, RecommendationEngine $engine) { $set = []; foreach ($engine->getBlacklistBuilders() as $blacklist) { $res = $result->get($blacklist->name()); foreach ($res->records() as $record) { if ($record->hasValue($blacklist->itemResultName())) { $node = $record->get($blacklist->itemResultName()); if ($node instanceof Node) { $set[$node->identity()] = $node; } } } } return $set; }