code: func WithOrdererEndpoint(key string) RequestOption {
  
  	return func(ctx context.Client, opts *requestOptions) error {
  
  		ordererCfg, found := ctx.EndpointConfig().OrdererConfig(key)
  		if !found {
  			return errors.Errorf("orderer not found for url : %s", key)
  		}
  
  		orderer, err := ctx.InfraProvider().CreateOrdererFromConfig(ordererCfg)
  		if err != nil {
  			return errors.WithMessage(err, "creating orderer from config failed")
  		}
  
  		return WithOrderer(orderer)(ctx, opts)
  	}
  }
docs: // WithOrdererEndpoint allows an orderer to be specified for the request.
  // The orderer will be looked-up based on the key argument.
  // key argument can be a name or url