python抽象类、抽象方法的实现

from abc import ABCMeta, abstractmethod#抽象类class Headers(object):    __metaclass__ = ABCMeta    def __init__(self):        self.headers = ''    @abstractmethod    def _getBaiduHeaders(self):pass    def __str__(self):        return str(self.headers)    def __rePR__(self):        return repr(self.headers)#实现类class BaiduHeaders(Headers):    def __init__(self, url, username, passWord):        self.url = url        self.headers = self._getBaiduHeaders(username, password)    def _getBaiduHeaders(self, username, password):        client = GLOBAL_SUDS_CLIENT.Client(self.url)        headers = client.factory.create('ns0:AuthHeader')        headers.username = username        headers.password = password        headers.token = _baidu_headers['token']        return headers