def __init__(self, name, host='127.0.0.1', port=27017):
        self.name = name
        self.host = host
        self.port = port
def __init__(self, saddr, gaddr, glen):
        self.saddr = saddr
        self.gaddr = gaddr
        self.glen = glen
        if ip_address(self.saddr).version != \
           ip_address(self.gaddr).version:
            raise ValueError('Source and group addresses must be of the '
                             'same address family.')