Phalcon\Mvc\Model\Behavior\NestedSet::addNode PHP Method

    private function addNode(ModelInterface $target, $key, $levelUp, array $attributes = null)
    {
        $owner = $this->getOwner();
        if (!$this->getIsNewRecord()) {
            throw new Exception('The node cannot be inserted because it is not new.');
        }
        if ($this->getIsDeletedRecord()) {
            throw new Exception('The node cannot be inserted because it is deleted.');
        }
        if ($target->getIsDeletedRecord()) {
            throw new Exception('The node cannot be inserted because target node is deleted.');
        }
        if ($owner == $target) {
            throw new Exception('The target node should not be self.');
        }
        if (!$levelUp && $target->isRoot()) {
            throw new Exception('The target node should not be root.');
        }
        if ($this->hasManyRoots) {
            $owner->{$this->rootAttribute} = $target->{$this->rootAttribute};
        }
        $db = $this->getDbHandler($owner);
        $db->begin();
        try {
            $this->ignoreEvent = true;
            $this->shiftLeftRight($key, 2);
            $this->ignoreEvent = false;
            $owner->{$this->leftAttribute} = $key;
            $owner->{$this->rightAttribute} = $key + 1;
            $owner->{$this->levelAttribute} = $target->{$this->levelAttribute} + $levelUp;
            $this->ignoreEvent = true;
            $result = $owner->create($attributes);
            $this->ignoreEvent = false;
            if (!$result) {
                $db->rollback();
                $this->ignoreEvent = false;
                return false;
            }
            $db->commit();
        } catch (\Exception $e) {
            $db->rollback();
            $this->ignoreEvent = false;
            throw $e;
        }
        return true;
    }