# -*- coding:UTF-8 -*-import abcclass Handler(metaclass=abc.ABCMeta):    def __init__(self):        self._successor = None    def set_successor(self, successor):        self._successor = successor    @abc.abstractmethod    def handle_request(self, request):        passclass ConcreteHandler1(Handler):    def handle_request(self, request):        if request >= 0 and request < 10:            print("{}处理请求{}".format(self.__class__.__name__, request))        elif self._successor != None:            self._successor.handle_request(request)class ConcreteHandler2(Handler):    def handle_request(self, request):        if request >= 10 and request < 20:            print("{}处理请求{}".format(self.__class__.__name__, request))        elif self._successor is not None:            self._successor.handle_request(request)class ConcreteHandler3(Handler):    def handle_request(self, request):        if request >= 20 and request < 30:            print("{}处理请求{}".format(self.__class__.__name__, request))        elif self._successor is not None:            self._successor.handle_request(request)if __name__ == "__main__":    h1 = ConcreteHandler1()    h2 = ConcreteHandler2()    h3 = ConcreteHandler3()    h1.set_successor(h2)    h2.set_successor(h3)    requests = [2, 5, 14, 22, 18, 3, 27, 20]    for request in requests:        h1.handle_request(request)