code: public Observable<ServiceResponse<List<VersionInfo>>> listWithServiceResponseAsync(UUID appId, ListVersionsOptionalParameter listOptionalParameter) {
          if (this.client.endpoint() == null) {
              throw new IllegalArgumentException("Parameter this.client.endpoint() is required and cannot be null.");
          }
          if (appId == null) {
              throw new IllegalArgumentException("Parameter appId is required and cannot be null.");
          }
          final Integer skip = listOptionalParameter != null ? listOptionalParameter.skip() : null;
          final Integer take = listOptionalParameter != null ? listOptionalParameter.take() : null;
  
          return listWithServiceResponseAsync(appId, skip, take);
      }
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