public T random() {
        List<T> items = ref.items;
        if (items.size() == 0) {
            return null;
        }
        if (items.size() == 1) {
            return items.get(0);
        }
        return items.get(ThreadLocalRandom.current().nextInt(items.size()));
    }
@Test
    void testChooserRandomForOneSizeList() {
        List<Pair<String>> list = new LinkedList<>();
        list.add(new Pair<>("test", 1));
        Chooser<String, String> chooser = new Chooser<>("test", list);
        String actual = chooser.random();
        assertNotNull(actual);
        assertEquals("test", actual);
    }