How to render HTML to Markdown?

Implementation
1

Using Commonmark java how to render html to markdown? I tried this example, but it is not rendering.

@Slf4j
class MarkdownTest {
    @Test
    void markdownTest() {
        String markdown = toMarkdown("<b> Hello World!</b>");
        log.info("markdown ==> {}", markdown);
    }

    String toMarkdown(String html) {
        Node htmlDocument = Parser.builder().build().parse(html);
        return MarkdownRenderer.builder().build().render(htmlDocument);
    }
}

Output:

markdown ==> <b> Hello World!</b>