json批量追加数据问题

import os
import json

path = r'path'      #原数据路径
json_list = os.listdir(path)
path_n = r'path'    #新数据路径
json_list_n = os.listdir(path_n)

i = 0
for f in json_list:
    if os.path.splitext(f)[-1] == '.json':
        i += 1
        print('原__',f)
        with open(os.path.join(path,f),'r',encoding='utf-8') as load_f:
            data_old  = json.load(load_f)
            shape = data_old['shapes'][-1]
            #print(shape)

for f_n in json_list_n:
    if os.path.splitext(f_n)[-1] == '.json':
        i += 1
        print('新__',f_n)
        with open(os.path.join(path_n,f_n),'r',encoding='utf-8') as dump_f:
            data_new  = json.load(dump_f)
            data_new['imageData'] = None
            shape_n = data_new['shapes']
            shape_n.append(shape)
            #print(shape_n)
        with open(os.path.join(path_n,f_n),'w',encoding='utf-8') as f_add:
            json.dump(data_new,f_add,indent=2)

有原4个json文件和新的4个json文件，我想要新的json数据分别更新到原的json里面。为什么我写的代码不能一对一更新?
比如我要的结果是: 原1.json更新到新1.json； 原2.json更新到新2.json。
但现在的结果是只能看到原4.json 统一更新到新 1 2 3 4。需要修改哪里呀

import os
import json

path = r'path'  # 原数据路径
json_list = os.listdir(path)
path_n = r'path'  # 新数据路径
json_list_n = os.listdir(path_n)

for index in range(len(json_list)):
    if os.path.splitext(json_list[index])[-1] == '.json':

        print('原__', json_list[index])
        with open(os.path.join(path, json_list[index]), 'r', encoding='utf-8') as load_f:
            data_old = json.load(load_f)
            shape = data_old['shapes'][-1]
            # print(shape)
        if os.path.splitext(json_list_n[index])[-1] == '.json':
            print('新__', json_list_n[index])
            with open(os.path.join(path_n, json_list_n[index]), 'r', encoding='utf-8') as dump_f:
                data_new = json.load(dump_f)
                data_new['imageData'] = None
                shape_n = data_new['shapes']
                shape_n.append(shape)
                # print(shape_n)
            with open(os.path.join(path_n, json_list_n[index]), 'w', encoding='utf-8') as f_add:
                json.dump(data_new, f_add, indent=2)

确保顺序一致，不值得话先排个序就行