docs: protected Example doFilter(Example example)
      {
          Example result = example;
  
          while ( !isBeginTag(result) && !isEndTag(result) )
          {
              if (result.nextSibling() == null)
              {
                  return getNextEndTag(example) == null ? null : example;
              }
              result = result.nextSibling();
          }
  
          return filter(result.nextSibling());
      }