code: public Set<String> classNames() {
      	String[] names = classSplit.split(className());
      	Set<String> classNames = new LinkedHashSet<>(Arrays.asList(names));
      	classNames.remove(""); // if classNames() was empty, would include an empty class
  
          return classNames;
      }
docs: Get all of the element's class names. E.g. on element {@code <div class="header gray">},
  returns a set of two elements {@code "header", "gray"}. Note that modifications to this set are not pushed to
  the backing {@code class} attribute; use the {@link #classNames(java.util.Set)} method to persist them.
  @return set of classnames, empty if no class attribute