code: public Observable<Page<ClassicAdministratorInner>> listAsync() {
          return listWithServiceResponseAsync()
              .map(new Func1<ServiceResponse<Page<ClassicAdministratorInner>>, Page<ClassicAdministratorInner>>() {
                  @Override
                  public Page<ClassicAdministratorInner> call(ServiceResponse<Page<ClassicAdministratorInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Gets service administrator, account administrator, and co-administrators for the subscription.
  
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;ClassicAdministratorInner&gt; object