delete ip address from this OS instance
        :param ip_address: the ip address to be deleted from this OS instance
        :param sync: If sync=True(default) synchronize with Ariane server. If sync=False,
        add the ipAddress object on list to be removed on next save().
        :return:

def del_ip_address(self, ip_address, sync=True):
        """
        delete ip address from this OS instance
        :param ip_address: the ip address to be deleted from this OS instance
        :param sync: If sync=True(default) synchronize with Ariane server. If sync=False,
        add the ipAddress object on list to be removed on next save().
        :return:
        """
        LOGGER.debug("OSInstance.del_ip_address")
        if not sync:
            self.ip_address_2_rm.append(ip_address)
        else:
            if ip_address.id is None:
                ip_address.sync()
            if self.id is not None and ip_address.id is not None:
                params = {
                    'id': self.id,
                    'ipAddressID': ip_address.id
                }
                args = {'http_operation': 'GET', 'operation_path': 'update/ipAddresses/delete', 'parameters': params}
                response = OSInstanceService.requester.call(args)
                if response.rc != 0:
                    LOGGER.warning(
                        'OSInstance.del_ip_address - Problem while updating OS instance ' + self.name +
                        '. Reason: ' + str(response.response_content) + '-' + str(response.error_message) +
                        " (" + str(response.rc) + ")"
                    )
                else:
                    self.ip_address_ids.remove(ip_address.id)
                    ip_address.ipa_os_instance_id = None
            else:
                LOGGER.warning(
                    'OSInstance.del_ip_address - Problem while updating OS instance ' + self.name +
                    '. Reason: IP Address ' + ip_address.ipAddress + ' id is None'
                )