def unregister_service(service, service_api)
      code, message, val = @proxy.unregisterService(@caller_id,
                                                    service,
                                                    service_api)
      if code == 1
        return true
      elsif code == 0
        puts message
        return true
      else
        raise message
      end
    end
def unregister_service(service, service_api)
      code, message, val = @proxy.unregisterService(@caller_id,
                                                    service,
                                                    service_api)
      if code == 1
        return true
      elsif code == 0
        puts message
        return true
      else
        raise message
      end
    end
unregister a service
 @param [String] service name of service
 @param [String] service_api service api uri
 @return [Boolean] true success
 @raise RuntimeError