code: public Future<Map<Integer, Set<MasteryPage>>> getMasteryPagesMultipleUsers(Integer... ids) {
          return new ApiFuture<>(() -> handler.getMasteryPagesMultipleUsers(ids));
      }
docs: Retrieve mastery pages for multiple users
  @param ids The ids of the users
  @return A map, mapping player ids to their respective mastery pages
  @see <a href=https://developer.riotgames.com/api/methods#!/620/1933>Official API documentation</a>