public Predicate convert(ScalarOperator operator) {
        if (operator == null) {
            return null;
        }
        return operator.accept(this, null);
    }
@Test
    public void testLike() {
        ConstantOperator value = ConstantOperator.createVarchar("ttt%");
        ScalarOperator op = new LikePredicateOperator(LikePredicateOperator.LikeType.LIKE, F1, value);
        Predicate result = CONVERTER.convert(op);
        Assert.assertTrue(result instanceof LeafPredicate);
        LeafPredicate leafPredicate = (LeafPredicate) result;
        Assert.assertTrue(leafPredicate.function() instanceof StartsWith);
        Assert.assertEquals("ttt", leafPredicate.literals().get(0).toString());
    }