code: public Observable<Page<NotificationHubResourceInner>> listAsync(final String resourceGroupName, final String namespaceName) {
          return listWithServiceResponseAsync(resourceGroupName, namespaceName)
              .map(new Func1<ServiceResponse<Page<NotificationHubResourceInner>>, Page<NotificationHubResourceInner>>() {
                  @Override
                  public Page<NotificationHubResourceInner> call(ServiceResponse<Page<NotificationHubResourceInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Lists the notification hubs associated with a namespace.
  
  @param resourceGroupName The name of the resource group.
  @param namespaceName The namespace name.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;NotificationHubResourceInner&gt; object