docs: static Elements filterOut(Collection<Element> elements, Collection<Element> outs) {
          Elements output = new Elements();
          for (Element el : elements) {
              boolean found = false;
              for (Element out : outs) {
                  if (el.equals(out)) {
                      found = true;
                      break;
                  }
              }
              if (!found)
                  output.add(el);
          }
          return output;
      }