@Override
    public void batchDeregisterService(String serviceName, String groupName, List<Instance> instances)
            throws NacosException {
        synchronized (redoService.getRegisteredInstances()) {
            List<Instance> retainInstance = getRetainInstance(serviceName, groupName, instances);
            batchRegisterService(serviceName, groupName, retainInstance);
        }
    }
@Test
    void testBatchDeregisterServiceWithoutCacheData() throws NacosException {
        assertThrows(NacosException.class, () -> {
            List<Instance> instanceList = new ArrayList<>();
            instance.setHealthy(true);
            instanceList.add(instance);
            client.batchDeregisterService(SERVICE_NAME, GROUP_NAME, instanceList);
        });
    }