static final String generateForFunction(RuleBuilderStep step, FunctionDescriptor<?> function) {
        return generateForFunction(step, function, 1);
    }
@Test
    public void generateFunctionWithNoParamGeneration() {
        RuleBuilderStep step = RuleBuilderStep.builder().function("function1").build();
        final FunctionDescriptor<Boolean> descriptor = FunctionUtil.testFunction(
                "function1", ImmutableList.of(
                        string("required").build(),
                        integer("optional").optional().build()
                ), Boolean.class
        ).descriptor();
        assertThat(ParserUtil.generateForFunction(step, descriptor)).isEqualTo(
                "function1()"
        );
    }