python委托（包装器）

Posted 2021-02-25

# learning python 3rd edition
# page 528
 
class Delegate(object):
    def __init__(self, wrapper):
        self.wrapper = wrapper
 
    def __getattr__(self, attribute):
        print "working on"
        return getattr(self.wrapper, attribute)
 
 
 
 
a_list = Delegate([1,2])
 
a_list.append(4)
working on