public MapBuilder getMap(String name) {
        MapBuilder a = mapBuilderMap.get(name);
        if (a == null) {
            validateMap(name);
            a = new MapBuilder(configDefinition, name);
            mapBuilderMap.put(name, a);
        }
        return a;
    }
@Test
    public void require_that_maps_are_created() {
        ConfigPayloadBuilder builder = new ConfigPayloadBuilder();
        ConfigPayloadBuilder.MapBuilder map = builder.getMap("foo");
        assertNotNull(map);
    }