code: public void getAPIInfo(String API, Callback<TokenInfo> callback) throws GuildWars2Exception, NullPointerException {
  		isParamValid(new ParamChecker(ParamType.API, API));
  		gw2API.getAPIInfo(API).enqueue(callback);
  	}
docs: For more info on TokenInfo API go <a href="https://wiki.guildwars2.com/wiki/API:2/tokeninfo">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      API key
  @param callback callback that is going to be used for {@link Call#enqueue(Callback)}
  @throws GuildWars2Exception  invalid API key
  @throws NullPointerException if given {@link Callback} is null
  @see TokenInfo API info