docs: public MenuItemType getMenuItemType() {
          if (knownType != KnownType.MENU_ITEM) {
              throw new IllegalArgumentException("getMenuItemType() can only be used with MENU_ITEM responses.");
          }
          final NumberField type = (NumberField)arguments.get(6);
          final MenuItemType result = MENU_ITEM_TYPE_MAP.get(type.getValue());
          if (result == null) {
              return MenuItemType.UNKNOWN;
          }
          return result;
      }