def __init__(self, request_driver, host=None, scheme='http'):
        """
        @type request_driver: RequestDriver
        """
        self.host = host
        self.scheme = scheme
        self.rd = request_driver
def __init__ ( self , request_driver , host = None , scheme = 'http' ) : self . host = host self . scheme = scheme self . rd = request_driver
@type request_driver: RequestDriver