def METHOD_NAME(self):
    if self._ip is None:
        if self.ip_family == AF_INET:
            self._ip = ipaddress(self._attr['MPTCP_PM_ADDR_ATTR_ADDR4'])
        else:
            self._ip = ipaddress(self._attr['MPTCP_PM_ADDR_ATTR_ADDR6'])
    return self._ip