code: public Observable<List<VersionInfo>> listAsync(UUID appId, ListVersionsOptionalParameter listOptionalParameter) {
          return listWithServiceResponseAsync(appId, listOptionalParameter).map(new Func1<ServiceResponse<List<VersionInfo>>, List<VersionInfo>>() {
              @Override
              public List<VersionInfo> call(ServiceResponse<List<VersionInfo>> response) {
                  return response.body();
              }
          });
      }
docs: Gets the application versions info.
  
  @param appId The application ID.
  @param listOptionalParameter the object representing the optional parameters to be set before calling this API
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;VersionInfo&gt; object