Transfer: https: //blog.csdn.net/rookinzhang/article/details/80259857
Python variable objects and immutable objects: https: //www.cnblogs.com/suxianglun/p/9013021.html
Transfer: https: //blog.csdn.net/rookinzhang/article/details/80259857
Python variable objects and immutable objects: https: //www.cnblogs.com/suxianglun/p/9013021.html