code: public static String getOperationName(final ModelNode op) {
          if (op.hasDefined(OP)) {
              return op.get(OP).asString();
          }
          throw ControllerClientLogger.ROOT_LOGGER.operationNameNotFound();
      }
docs: Returns the name of the operation.
  
  @param op the operation
  
  @return the name of the operation
  
  @throws IllegalArgumentException if the operation was not defined.