public static ServiceInfo selectInstances(ServiceInfo serviceInfo, String cluster) {
        return selectInstances(serviceInfo, cluster, false, false);
    }
@Test
    void testSelectInstances() {
        ServiceInfo serviceInfo = new ServiceInfo();
        serviceInfo.setGroupName("groupName");
        serviceInfo.setName("serviceName");
        serviceInfo.setChecksum("checkSum");
        serviceInfo.setAllIPs(false);
        ServiceInfo cluster = ServiceUtil.selectInstances(serviceInfo, "cluster");
        assertNotNull(cluster);
    }