外部链接:https://blog.csdn.net/qq_36357820/article/details/89513839
https://www.cnblogs.com/pejsidney/p/9548354.html
https://www.cnblogs.com/JentZhang/p/10044088.html
常用有2个方法,也是最基本的使用方法:
1、dumps:把字典转成json字符串
2、loads: 把json字符串转成字典