code: public final View findViewById(@IdRes final int viewId) {
          View view = null;
  
          if (views != null) {
              view = views.get(viewId);
          } else {
              views = new SparseArray<>();
          }
  
          if (view == null) {
              view = parentView.findViewById(viewId);
              views.put(viewId, view);
          }
  
          return view;
      }
docs: Returns the view, which belongs to a specific resource ID. If the view has already been
  referenced, the view, which is stored by the view holder, will be returned. Otherwise the
  method <code>findViewById(int):View</code> of the parent view, the view holder belongs to, is
  used to reference the view.
  
  @param viewId
  The resource ID of the view, which should be returned, as an {@link Integer} value.
  The ID must be a valid resource ID of a view, which belongs to the given parent view
  @return The view, which belongs to the given resource ID, as an instance of the class {@link
  View} or null, if no view with the given ID is available