How to use the @argdown/core.GraphMLExportPlugin function in @argdown/core

argdown.addPlugin(saveAsJSON, "save-as-json");
const stdoutJSON = new StdOutPlugin({ dataKey: "json" });
argdown.addPlugin(stdoutJSON, "stdout-json");

const dotExport = new DotExportPlugin();
argdown.addPlugin(dotExport, "export-dot");
const saveAsDot = new SaveAsFilePlugin({
  outputDir: "./dot",
  dataKey: "dot",
  extension: ".dot"
});
argdown.addPlugin(saveAsDot, "save-as-dot");
const stdoutDot = new StdOutPlugin({ dataKey: "dot" });
argdown.addPlugin(stdoutDot, "stdout-dot");

const graphMLExport = new GraphMLExportPlugin();
argdown.addPlugin(graphMLExport, "export-graphml");
const saveAsGraphML = new SaveAsFilePlugin({
  outputDir: "./graphml",
  dataKey: "graphml",
  extension: ".graphml"
});
argdown.addPlugin(saveAsGraphML, "save-as-graphml");
const stdoutGraphML = new StdOutPlugin({ dataKey: "graphml" });
argdown.addPlugin(stdoutGraphML, "stdout-graphml");

const dotToSvgExport = new DotToSvgExportPlugin();
argdown.addPlugin(dotToSvgExport, "export-svg");
const saveSvgAsSvg = new SaveAsFilePlugin({
  outputDir: "./svg",
  dataKey: "svg",
  extension: ".svg"

const dataPlugin = new DataPlugin();
const modelPlugin = new ModelPlugin();
const regroupPlugin = new RegroupPlugin();
const colorPlugin = new ColorPlugin();

const htmlExport = new HtmlExportPlugin({
  headless: true
});
const jsonExport = new JSONExportPlugin({ removeEmbeddedRelations: true });
const preselectionPlugin = new PreselectionPlugin();
const statementSelectionPlugin = new StatementSelectionPlugin();
const argumentSelectionPlugin = new ArgumentSelectionPlugin();
const mapPlugin = new MapPlugin();
const groupPlugin = new GroupPlugin();
const dotExport = new DotExportPlugin();
const graphMLExport = new GraphMLExportPlugin();
import primer from "!!raw-loader!../public/examples/argdown-primer.argdown";

app.addPlugin(parserPlugin, "parse-input");
app.addPlugin(dataPlugin, "build-model");
app.addPlugin(modelPlugin, "build-model");
app.addPlugin(regroupPlugin, "build-model");
app.addPlugin(colorPlugin, "colorize");
app.addPlugin(preselectionPlugin, "build-map");
app.addPlugin(statementSelectionPlugin, "build-map");
app.addPlugin(argumentSelectionPlugin, "build-map");
app.addPlugin(mapPlugin, "build-map");
app.addPlugin(groupPlugin, "build-map");
app.addPlugin(new ClosedGroupPlugin(), "transform-closed-groups");
app.addPlugin(htmlExport, "export-html");
app.addPlugin(dotExport, "export-dot");
app.addPlugin(graphMLExport, "export-graphml");