如何理解Python装饰器?

def inject_check(method):    def my_method(*args):        print "before"        method(*args)        print "after"    return my_method############################    #class Demo(object):#    def hello(self):#        pri迹绩管啃攮救归寻害默nt "hello"#    hello=inject_check(hello)##########################    class Demo(object):    @inject_check    def hello(self):        print "hello"        d = Demo()d.hello()就是在函数上加个包装，如上面代码中的hello函数加上@inject_check装饰器，等价于将函数hello重新赋值：hello=inject_check(hello)