SimpleResponseBuilder && ResponseSynthesizer are missing

  //response builder
  let customResponseBuilder = new llamaIndex.SimpleResponseBuilder(
    customServiceContext,
    customPrompt
  );

  let customSynthesizer = new llamaIndex.ResponseSynthesizer({
    responseBuilder: customResponseBuilder,
    serviceContext: customServiceContext,
  });

both are missing for api docs on llamaindex website as well as web are are likely depracted, how to fix this?