is和==

参考 https://blog.csdn.net/qq_41597912/article/details/81459804

a = "hello"
b = "hello"
a is b # True
a == b # True

a = [1]
b = [1]
a is b # False
a == b # True

这是因为None在Python里是个单例对象，一个变量如果是None，它一定和None指向同一个内存地址。