public static void batchSetInstanceIdIfEmpty(List<Instance> instances, String groupedServiceName) {
        if (null != instances) {
            for (Instance instance : instances) {
                setInstanceIdIfEmpty(instance, groupedServiceName);
            }
        }
    }
@Test
    void testBatchSetInstanceIdIfEmpty() {
        final List<Instance> instances = new ArrayList<>();
        Instance instance1 = new Instance();
        instance1.setServiceName("test");
        Instance instance2 = new Instance();
        instance2.setServiceName("test");
        Instance instance3 = new Instance();
        instance3.setServiceName("test");
        instances.add(instance1);
        instances.add(instance2);
        instances.add(instance3);
        InstanceUtil.batchSetInstanceIdIfEmpty(instances, "test");
        assertNotNull(instance1.getInstanceId());
        assertNotNull(instance2.getInstanceId());
        assertNotNull(instance3.getInstanceId());
    }