public <ConfigType extends ConfigInstance> ConfigType toInstance(Class<ConfigType> clazz, String configId) {
        return ConfigInstanceUtil.getNewInstance(clazz, configId, this);
    }
@Test
    public void test_map_of_map() {
        Slime slime = new Slime();
        Cursor map = slime.setObject().setObject("nestedmap").setObject("my-nested").setObject("inner");
        map.setLong("one", 1);
        map.setLong("two", 2);

        MaptypesConfig config = new ConfigPayload(slime).toInstance(MaptypesConfig.class, "");
        assertThat(config.nestedmap("my-nested").inner("one"), is(1));
        assertThat(config.nestedmap("my-nested").inner("two"), is(2));
    }