code: public Observable<ServiceResponse<List<WorkbookInner>>> listByResourceGroupWithServiceResponseAsync(String resourceGroupName, CategoryType category, List<String> tags, Boolean canFetchContent) {
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (category == null) {
              throw new IllegalArgumentException("Parameter category is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          Validator.validate(tags);
          String tagsConverted = this.client.serializerAdapter().serializeList(tags, CollectionFormat.CSV);
          return service.listByResourceGroup(this.client.subscriptionId(), resourceGroupName, category, tagsConverted, canFetchContent, this.client.apiVersion(), this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<List<WorkbookInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<List<WorkbookInner>>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<PageImpl1<WorkbookInner>> result = listByResourceGroupDelegate(response);
                          List<WorkbookInner> items = null;
                          if (result.body() != null) {
                              items = result.body().items();
                          }
                          ServiceResponse<List<WorkbookInner>> clientResponse = new ServiceResponse<List<WorkbookInner>>(items, result.response());
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Get all Workbooks defined within a specified resource group and category.
  
  @param resourceGroupName The name of the resource group.
  @param category Category of workbook to return. Possible values include: 'workbook', 'TSG', 'performance', 'retention'
  @param tags Tags presents on each workbook returned.
  @param canFetchContent Flag indicating whether or not to return the full content for each applicable workbook. If false, only return summary content for workbooks.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;WorkbookInner&gt; object