自关联的树分类

def common_tree(datas):
    res = {}
    if len(datas) > 0:
        for v in datas:
            v["parent_id"] = v["parent_id"][0] if v["parent_id"] else 0
            res.setdefault(v["id"], v).update(v)
            res.setdefault(v["parent_id"], {}).setdefault("children", []).append(res.get(v["id"], v))
        return res[0]["children"]
    return []