@Override
    public ScalarOperator visitCloneOperator(CloneOperator operator, Void context) {
        return shuttleIfUpdate(operator);
    }
@Test
    void testCloneOperator() {
        BinaryPredicateOperator binary1 = new BinaryPredicateOperator(BinaryType.EQ,
                new ColumnRefOperator(1, INT, "id", true), ConstantOperator.createInt(1));
        CloneOperator clone = new CloneOperator(binary1);
        {
            ScalarOperator newOperator = shuttle.visitCloneOperator(clone, null);
            assertEquals(clone, newOperator);
        }
        {
            ScalarOperator newOperator = shuttle2.visitCloneOperator(clone, null);
            assertEquals(clone, newOperator);
        }
    }