code: public Future<Map<String, List<LeagueItem>>> getLeagueEntries(String... teamIds) {
          return new ApiFuture<>(() -> handler.getLeagueEntries(teamIds));
      }
docs: Get a listing of all league entries in the teams' leagues
  @param teamIds The ids of the teams
  @return A mapping of teamIds to lists of league entries
  @see <a href=https://developer.riotgames.com/api/methods#!/593/1861>Official API documentation</a>