code: public static void run(Appendable out, String... inputs) throws IOException {
      PolicyFactory policyBuilder = new HtmlPolicyBuilder()
        .allowAttributes("src").onElements("img")
        .allowAttributes("href").onElements("a")
        // Allow some URLs through.
        .allowStandardUrlProtocols()
        .allowElements(
            "a", "label", "h1", "h2", "h3", "h4", "h5", "h6",
            "p", "i", "b", "u", "strong", "em", "small", "big", "pre", "code",
            "cite", "samp", "sub", "sup", "strike", "center", "blockquote",
            "hr", "br", "col", "font", "span", "div", "img",
            "ul", "ol", "li", "dd", "dt", "dl", "tbody", "thead", "tfoot",
            "table", "td", "th", "tr", "colgroup", "fieldset", "legend"
        )
        .withPostprocessor(
            new HtmlStreamEventProcessor() {
              public HtmlStreamEventReceiver wrap(HtmlStreamEventReceiver sink) {
                return new AppendDomainAfterText(sink);
              }
            }
        ).toFactory();
  
      out.append(policyBuilder.sanitize(Joiner.on('\n').join(inputs)));
    }
docs: Sanitizes inputs to out.