protected List<String> create(String[] elements) {
                // For this test we trust ArrayList works
                List<String> list = new ArrayList<>();
                Collections.addAll(list, elements);
                return new AbstractSequentialList<String>() {
                  @Override
                  public int size() {
                    return list.size();
                  }

  // For example:
  // class Holder<T> {
  //   void set(T data) {...}
  // }
  // Holder<List<?>> should *not* resolve the set() method to set(List<?> data).
  // Instead, it should create a capture of the wildcard so that set() rejects any List<T>.
  private static class WildcardCapturer {

    static final WildcardCapturer INSTANCE = new WildcardCapturer();

    public boolean equals(@Nullable Object obj) {
      if (obj instanceof WildcardType) {
        WildcardType that = (WildcardType) obj;
        return lowerBounds.equals(Arrays.asList(that.getLowerBounds()))
            && upperBounds.equals(Arrays.asList(that.getUpperBounds()));
      }
      return false;
    }

    @Override
    public int hashCode() {
      return lowerBounds.hashCode() ^ upperBounds.hashCode();

  // For example:
  // class Holder<T> {
  //   void set(T data) {...}
  // }
  // Holder<List<?>> should *not* resolve the set() method to set(List<?> data).
  // Instead, it should create a capture of the wildcard so that set() rejects any List<T>.
  private static class WildcardCapturer {

    static final WildcardCapturer INSTANCE = new WildcardCapturer();

    public boolean equals(@Nullable Object obj) {
      if (obj instanceof WildcardType) {
        WildcardType that = (WildcardType) obj;
        return lowerBounds.equals(Arrays.asList(that.getLowerBounds()))
            && upperBounds.equals(Arrays.asList(that.getUpperBounds()));
      }
      return false;
    }

    @Override
    public int hashCode() {
      return lowerBounds.hashCode() ^ upperBounds.hashCode();

            fail();
        } catch (final ChildUrlsException e) {
            final Set<RequestData> urlSet = e.getChildUrlList();
            assertEquals(5, urlSet.size());
            final List<String> urlList = urlSet.stream().map(x -> x.getUrl()).sorted().toList();
            assertEquals("ftp://localhost:10021/dir1", urlList.get(0));
            assertEquals("ftp://localhost:10021/dir2", urlList.get(1));