code: Optional<String> getLambdaClassDescription(String className) {
      int slashIndex = className.lastIndexOf('/');
      if (slashIndex > 0) {
        String name = className.substring(0, slashIndex);
        String desc = _names.get(name);
        if (desc == null || desc.isEmpty()) {
          return Optional.empty();
        } else {
          return Optional.of(desc);
        }
      }
  
      return Optional.empty();
    }
docs: /*package private