@Override
    public String toString() {
        return targetMap.toString();
    }
@Test
    void testToString() {
        Map<String, Object> map = new LowerCaseLinkHashMap<>(lowerCaseLinkHashMap);
        Assertions.assertEquals(lowerCaseLinkHashMap.toString(), map.toString());
        map.put("toString", "toString2");
        Assertions.assertNotEquals(lowerCaseLinkHashMap.toString(), map.toString());
    }