public function siblingsOf(ChildCategory $category, ConnectionInterface $con = null)
    {
        if ($category->isRoot()) {
            return $this->
                add(ChildCategory::LEVEL_COL, '1<>1', Criteria::CUSTOM);
        } else {
            return $this
                ->childrenOf($category->getParent($con))
                ->prune($category);
        }
    }