protected function _insertParent($entity) {
		extract($this->_config);
		$parent = $this->_getById($entity->$parent);
		if ($parent) {
			$r = $parent->$right;
			$this->_update($r, '+', 2, $this->_scope($entity));
			$entity->set([
				$left => $r,
				$right => $r + 1
			]);
		}
	}