我有一个从数据库（MySQL）中检索到的JSON字符串，我需要为JSON字符串中的daysOff属性添加另一个值。将新值附加到JSON字符串后，我需要用新值更新表。
我是Python的新手，我知道字符串是不可变的，我遇到的麻烦是遍历数组以将新值添加到daysOff属性
这是我目前所掌握的情况：

import mysql.connector as mysqlConnector
import sys
import json
from datetime import date

query = "SELECT option_value FROM my_tbl WHERE option_name='my_holiday_settings'"
    try:
        cur.execute(query)
        myresult = cur.fetchall()
        for x in myresult:
            dictionary = json.loads(*x)
            key = 'daysOff'
            checkKey(dictionary, key)
            print(dict)
            print(dictionary)
            print(type(dictionary))
    except Exception as e:
        print('error:', e)
    finally:
        cur.close()

def checkKey(dict, key):
    if key in dict.keys():
        test_dict = {"name":"test","startDate":"9999-01-01","endDate":"9999-09-09","repeat":"0"}
        dict[key]=test_dict
        print("value updated =", 600)
    else:
        print("Not Exist")

这是我的JSON

{
  "notifications": {
    "whatsAppBusinessID": "None",
    "whatsAppLanguage": "Alien"
  },
  "daysOff": [
    {
      "name": "Xmas",
      "startDate": "2022-01-09",
      "endDate": "2022-01-09",
      "repeat": true
    },
    {
      "name": "Australia Day",
      "startDate": "2022-01-26",
      "endDate": "2022-01-26",
      "repeat": true
    },
    {
      "name": "Good Friday",
      "startDate": "2022-04-15",
      "endDate": "2022-04-15",
      "repeat": true
    },
    {
      "name": "Holy Saturday",
      "startDate": "2022-04-16",
      "endDate": "2022-04-16",
      "repeat": true
    }
  ]
}