public static boolean isEmpty(Collection<?> col) {
        return !isNotEmpty(col);
    }
@Test
    public void testIsEmpty() {
        Map<String, Object> map = new HashMap<>();
        Assertions.assertTrue(CollectionUtils.isEmpty(map));
        map.put("k", "v");
        Assertions.assertFalse(CollectionUtils.isEmpty(map));
        map = null;
        Assertions.assertTrue(CollectionUtils.isEmpty(map));
    }