类的特殊方法

class foo:
    def __init__(self):
        print('init')
    def __call__(self, *args, **kwargs):
        print('call')
        return 1
    def __getitem__(self, item):
        print(item)
    def __setitem__(self, key, value):
        print(key,value)
    def __delitem__(self, key):
        print(key)
r = foo()
r() #__call__
r['ffff'] # __getitem__
r['fffggdg'] = 123 # __setitem__
del r['hfdfbdfb'] # __delitem__

class foo:
    def __init__(self,args):
        self.xo = args
    def __str__(self):
        return self.xo
r = foo('出错啦')
print(r)