code: private int getItemViewType(Class prototypeClass) {
      int itemViewType = -1;
      for (Renderer renderer : prototypes) {
        if (renderer.getClass().equals(prototypeClass)) {
          itemViewType = getPrototypeIndex(renderer);
          break;
        }
      }
      if (itemViewType == -1) {
        throw new PrototypeNotFoundException(
            "Review your RendererBuilder implementation, you are returning one"
                + " prototype class not found in prototypes collection");
      }
      return itemViewType;
    }
docs: Return the Renderer class associated to the prototype.
  
  @param prototypeClass used to search the renderer in the prototypes collection.
  @return the prototype index associated to the prototypeClass.