public void attach_and_detach_node()
        {
            String hostName = "192.168.20.166";
            int    port     = 46000;

            SequoiaDB.Node data_node = null;

            // check whether it is in the cluster environment or not
            if (!Constants.isClusterEnv(sdb))
            {
                Console.WriteLine("It's not a cluster environment.");
                return;
            }
            // detach node
            group.DetachNode(hostName, port, null);

            // check
            data_node = group.GetNode(hostName, port);
            Assert.IsNull(data_node);

            //attach node
            group.AttachNode(hostName, port, null);

            // check
            data_node = group.GetNode(hostName, port);
            Assert.IsNotNull(data_node);
        }