json字符串的读与写

import json
def op_data(filename,dic=None):
    if dic:
        with open(filename,'w',encoding='utf-8') as fw:
            json.dump(dic,fw,ensure_ascii=False,indent=4)#json串写入文件中
    else:
        with open(filename,encoding='utf-8') as fr:
            return json.load(fr)#文件里面内容写入json格式

def add_goods(good):
    global goods
    temp = {}
    thing  = input("请输入商品：").strip()
    nums = input("请输入总量：").strip()
    prices = input("请输入价格：").strip()
    colors = input("请输入颜色：").strip()
    temp['num'] = nums
    temp['price'] = prices
    temp['color'] = colors
    good[thing] = temp
    return goods

FILE_NAME = "goods.json"
goods = op_data(FILE_NAME)
#print(goods)
all_goods = add_goods(goods)
op_data(FILE_NAME,all_goods)