分类标签children，具体内容是？

class getcontentTag(MethodView): def get(self): try: _sql_cate = "SELECT * FROM cate_a" cate_res = db.session.execute(text(_sql_cate)).fetchall() _sql_tag = "SELECT * FROM tag_a" tag_res = db.session.execute(text(_sql_tag)).fetchall() #将查询结果转换为字典列表 categories = [dict(row._asdict()) for row in cate_res] tags = [dict(row._asdict()) for row in tag_res] # 构建类别字典，key为id，value为类别信息 category_dict = {category['id']: category for category in categories} # print(category_dict) # # 初始化children列表 for category in categories: # 空列表，存储子标签 category['children'] = [] # print(category) # #将标签添加到对应的类别中 for tag in tags: # print(tag) # # 如pid在category_dict中，则将标签添加到对应的类别中 if tag['pid'] in category_dict: # # 将标签添加到对应的类别的children列表中 category_dict[tag['pid']]['children'].append(tag) # # 提取根类别 result = [category for category in categories if category['pid'] == 0] return jsonify({'code': Code.OK, 'msg': code_desc[Code.OK], 'data':result}) except Exception as e: return jsonify({'code': Code.ERROR, 'msg': code_desc[Code.ERROR], 'data': None}) { "code": 200, "data": [ { "children": [ { "id": 1, "name": "体育鞋测评", "pid": 1 }, { "id": 2, "name": "耳机评测", "pid": 1 } ], "id": 1, "name": "产品评测", "pid": 0 }, { "children": [ { "id": 3, "name": "扑克", "pid": 2