How to use the @jupyterlab/completer/src.Completer.Renderer function in @jupyterlab/completer

import { framePromise, sleep } from '@jupyterlab/testutils';
const TEST_ITEM_CLASS = 'jp-TestItem';

const ITEM_CLASS = 'jp-Completer-item';

const ACTIVE_CLASS = 'jp-mod-active';

function createEditorWidget(): CodeEditorWrapper {
  let model = new CodeEditor.Model();
  let factory = (options: CodeEditor.IOptions) => {
    return new CodeMirrorEditor(options);
  };
  return new CodeEditorWrapper({ factory, model });
}

class CustomRenderer extends Completer.Renderer {
  createItemNode(
    item: Completer.IItem,
    typeMap: Completer.TypeMap,
    orderedTypes: string[]
  ): HTMLLIElement {
    let li = super.createItemNode(item, typeMap, orderedTypes);
    li.classList.add(TEST_ITEM_CLASS);
    return li;
  }
}

class LogWidget extends Completer {
  events: string[] = [];

  methods: string[] = [];