public function getRoot()
    {
        $path = $this->owner->getPath();
        $path = array_shift($path);
        $query = $this->owner->find();
        /** @var \yii\db\ActiveQuery $query */
        $query
            ->andWhere([$this->keyColumn => $path])
            ->limit(1);
        $query->multiple = false;
        return $query;
    }