class Foo:
    def __init__(self):
        pass

    def __call__(self, *args, **kwargs):
        pass

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

    def __setitem__(self, key, value):
        print(key,value)
        pass

    def __delitem__(self, key):
        pass

# 调用__int__方法
Foo()

# 调用__call__方法
obj = Foo()
obj()

#调用__getitem__方法
obj = Foo()
obj[‘k1‘]

#调用__setitem__方法
obj = Foo()
obj[‘k1‘] = 123

#__delitem__
obj = Foo()
del obj[‘k1‘]