code: <T extends Entity> T executeOperation(Class<T> clazz, Entity subject,
                                            String operationName) throws UnsupportedOperationException {
          Oid operationResult = executeOperation(subject, operationName);
          AssetID id = new AssetID(operationResult.getToken());
  
          return createWrapper(clazz, id, false);
      }
docs: Executes an Operation on an Entity, assuming it is safe to do so.
  
  @param clazz         Class of expected Entity to return.
  @param subject       asset will be found for.
  @param operationName operator name.
  @return object identifier.
  @throws UnsupportedOperationException in case invalid state for the
  Operation.