code: static boolean retainPresenterInstance(boolean keepPresenterInstance, Controller controller) {
  
      return keepPresenterInstance && (controller.getActivity().isChangingConfigurations()
          || !controller.getActivity().isFinishing()) && !controller.isBeingDestroyed();
    }
docs: Determines whether or not a Presenter Instance should be kept
  
  @param keepPresenterInstance true, if the delegate has enabled keep