@Override
    public <T> T merge(T detachedObject) {
        Map<Object, Object> alreadyPersisted = new HashMap<Object, Object>();
        return persist(detachedObject, alreadyPersisted, RCascadeType.MERGE);
    }
@Test
    public void testNullValue() {
        TestClass ti = new TestClass("3");
        TestClass liveObject = redisson.getLiveObjectService().merge(ti);

        liveObject.setCode("test");
        liveObject.setCode(null);
        assertThat(liveObject.getCode()).isNull();

        liveObject.setCode("123");
        assertThat(liveObject.getCode()).isEqualTo("123");
    }