def lookup_service(service)
      code, message, uri = @proxy.lookupService(@caller_id, service)
      if code == 1
        uri
      else
        false
      end
    end
def lookup_service(service)
      code, message, uri = @proxy.lookupService(@caller_id, service)
      if code == 1
        uri
      else
        false
      end
    end
look up a service by name
 @param [String] service name of service
 @return [String, nil] URI of service if found, nil not found.