code: public static Response failure(SessionId sessionId, Throwable reason) {
      Response response = new Response();
      response.setSessionId(sessionId != null ? sessionId.toString() : null);
      response.setValue(reason);
      response.setStatus(ERROR_CODES.toStatusCode(reason));
      response.setState(ERROR_CODES.toState(response.getStatus()));
      return response;
    }
docs: Creates a response object for a failed command execution.
  
  @param sessionId ID of the session that executed the command.
  @param reason the failure reason.
  @return the new response object.