private function handleAfter(
        ModelId $after,
        RelationshipManager $relationships,
        ModelCollector $collector,
        ModelInterface $model
    ) {
        $sibling = $collector->getModel($after);

        if (!$sibling || $relationships->isRoot($sibling)) {
            $relationships->setRoot($model);
            return;
        }

        $parent = $collector->searchParentOf($sibling);
        $relationships->setParent($model, $parent);
    }