code: public Observable<List<VirtualMachineImageResourceInner>> listSkusAsync(String location, String publisherName, String offer) {
          return listSkusWithServiceResponseAsync(location, publisherName, offer).map(new Func1<ServiceResponse<List<VirtualMachineImageResourceInner>>, List<VirtualMachineImageResourceInner>>() {
              @Override
              public List<VirtualMachineImageResourceInner> call(ServiceResponse<List<VirtualMachineImageResourceInner>> response) {
                  return response.body();
              }
          });
      }
docs: Gets a list of virtual machine image SKUs for the specified location, publisher, and offer.
  
  @param location The name of a supported Azure region.
  @param publisherName A valid image publisher.
  @param offer A valid image publisher offer.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;VirtualMachineImageResourceInner&gt; object