code: public void getPvPStatInfo(String api, Callback<PvPStat> callback) throws GuildWars2Exception, NullPointerException {
  		isParamValid(new ParamChecker(ParamType.API, api));
  		gw2API.getPvPStatInfo(api).enqueue(callback);
  	}
docs: For more info on pvp stat API go <a href="https://wiki.guildwars2.com/wiki/API:2/pvp/stats">here</a><br/>
  Give user the access to {@link Callback#onResponse(Call, Response)} and {@link Callback#onFailure(Call, Throwable)} methods for custom interactions
  
  @param api      Guild Wars 2 API key
  @param callback callback that is going to be used for {@link Call#enqueue(Callback)}
  @throws NullPointerException if given {@link Callback} is empty
  @throws GuildWars2Exception  invalid api key
  @see PvPStat pvp stat info