code: function (args) {
                  args.HasError = false;
                  args.ErrorMessage = "";
  
                  if (this.Items !== undefined && this.Items.length === 0) {
                      args.HasError = true;
                      args.ErrorMessage = "At least one item must be on invoice.";
                      args.TranslateArgs = { TranslateId: "AnyItem", MessageArgs: undefined };
                      return;
                  }
              }
docs: at least one item must be filled