code: public Observable<List<VirtualMachineExtensionImageInner>> listVersionsAsync(String location, String publisherName, String type) {
          return listVersionsWithServiceResponseAsync(location, publisherName, type).map(new Func1<ServiceResponse<List<VirtualMachineExtensionImageInner>>, List<VirtualMachineExtensionImageInner>>() {
              @Override
              public List<VirtualMachineExtensionImageInner> call(ServiceResponse<List<VirtualMachineExtensionImageInner>> response) {
                  return response.body();
              }
          });
      }
docs: Gets a list of virtual machine extension image versions.
  
  @param location The name of a supported Azure region.
  @param publisherName the String value
  @param type the String value
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;VirtualMachineExtensionImageInner&gt; object