#__getitem__  __setitem__  __delitem__运行设置key value值了
class fun:

    def __init__(self):
        print('test')

    def run(self):
        print('run')

    def __getitem__(self, item):
        print('__getitem__','item:',item)

    def __setitem__(self, key, value):
        print('__setitem__','key:',key,'value:',value)
        self.__dict__[key] = value  #设置字典值,print(f.__dict__)否则打印为空

    def __delitem__(self, key):
        print('__delitem__','key',key)
        self.__dict__.pop(key)     #删除字典值
f = fun()
f.run()
f['sn'] = 1231

f['name'] = 1   #设置值的时候,执行__setitem__
f['name']       #获取值的时候,执行__getitem__
del f['name']   #删除值的时候,执行__delitem__

print(f.__dict__)  #结果是{'sn': 1231}