code: public Observable<Page<DataMigrationServiceInner>> listAsync() {
          return listWithServiceResponseAsync()
              .map(new Func1<ServiceResponse<Page<DataMigrationServiceInner>>, Page<DataMigrationServiceInner>>() {
                  @Override
                  public Page<DataMigrationServiceInner> call(ServiceResponse<Page<DataMigrationServiceInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Get services in subscription.
  The services resource is the top-level resource that represents the Data Migration Service. This method returns a list of service resources in a subscription.
  
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;DataMigrationServiceInner&gt; object