private CompletionSorterImpl enhanced(ClassifierFactory<LookupElement> classifierFactory, int index) {
    final List<ClassifierFactory<LookupElement>> copy = new ArrayList<>(myMembers);
    copy.add(index, classifierFactory);
    return new CompletionSorterImpl(copy);
  }
private CompletionSorterImpl enhanced(ClassifierFactory<LookupElement> classifierFactory, int index)