How to use the @jupyterlab/coreutils.PageConfig.getOption function in @jupyterlab/coreutils

private connect_socket(options: ISocketConnectionOptions): LSPConnection {
    let { virtual_document, language } = options;

    const wsBase = PageConfig.getBaseUrl().replace(/^http/, 'ws');
    const rootUri = PageConfig.getOption('rootUri');
    const documentUri = URLExt.join(rootUri, virtual_document.uri);
    const serverUri = URLExt.join('ws://jupyter-lsp', language);
    let socket = new WebSocket(URLExt.join(wsBase, 'lsp', language));

    let connection = new LSPConnection({
      languageId: language,
      serverUri,
      rootUri,
      documentUri,
      documentText: () => {
        // NOTE: Update is async now and this is not really used, as an alternative method
        // which is compatible with async is used.
        // This should be only used in the initialization step.
        // if (main_connection.isConnected) {
        //  console.warn('documentText is deprecated for use in JupyterLab LSP');
        // }

let wFactory = new NotebookWidgetFactory({
    name: 'Notebook',
    modelName: 'notebook',
    fileTypes: ['notebook'],
    defaultFor: ['notebook'],
    preferKernel: true,
    canStartKernel: true,
    rendermime,
    contentFactory,
    mimeTypeService: editorServices.mimeTypeService
  });
  docRegistry.addModelFactory(mFactory);
  docRegistry.addWidgetFactory(wFactory);

  let notebookPath = PageConfig.getOption('notebookPath');
  let nbWidget = docManager.open(notebookPath) as NotebookPanel;
  let palette = new CommandPalette({ commands });

  const editor =
    nbWidget.content.activeCell && nbWidget.content.activeCell.editor;
  const model = new CompleterModel();
  const completer = new Completer({ editor, model });
  const connector = new KernelConnector({ session: nbWidget.session });
  const handler = new CompletionHandler({ completer, connector });

  // Set the handler's editor.
  handler.editor = editor;

  // Listen for active cell changes.
  nbWidget.content.activeCellChanged.connect((sender, cell) => {
    handler.editor = cell && cell.editor;

let useCapture = true;

  // Setup the keydown listener for the document.
  document.addEventListener(
    'keydown',
    event => {
      commands.processKeydownEvent(event);
    },
    useCapture
  );

  let rendermime = new RenderMimeRegistry({
    initialFactories: initialFactories,
    latexTypesetter: new MathJaxTypesetter({
      url: PageConfig.getOption('mathjaxUrl'),
      config: PageConfig.getOption('mathjaxConfig')
    })
  });

  let opener = {
    open: (widget: Widget) => {
      // Do nothing for sibling widgets for now.
    }
  };

  let docRegistry = new DocumentRegistry();
  let docManager = new DocumentManager({
    registry: docRegistry,
    manager,
    opener
  });
  let mFactory = new NotebookModelFactory({});

let wFactory = new NotebookWidgetFactory({
    name: 'Notebook',
    modelName: 'notebook',
    fileTypes: ['notebook'],
    defaultFor: ['notebook'],
    preferKernel: true,
    canStartKernel: true,
    rendermime,
    contentFactory,
    mimeTypeService: editorServices.mimeTypeService
  });
  docRegistry.addModelFactory(mFactory);
  docRegistry.addWidgetFactory(wFactory);

  let notebookPath = PageConfig.getOption('notebookPath');
  let nbWidget = docManager.open(notebookPath) as NotebookPanel;

  // Create menu bar.
  let menuBar = new MenuBar();
  menuBar.addClass('notebookMenuBar');

  const editor =
    nbWidget.content.activeCell && nbWidget.content.activeCell.editor;
  const model = new CompleterModel();
  const completer = new Completer({ editor, model });
  const connector = new KernelConnector({ session: nbWidget.session });
  const handler = new CompletionHandler({ completer, connector });

  // Set the handler's editor.
  handler.editor = editor;

readonly defaultWorkspace: string;
  }

  /**
   * The default application info.
   */
  export const defaultInfo: IInfo = {
    name: PageConfig.getOption('appName') || 'JupyterLab',
    namespace: PageConfig.getOption('appNamespace'),
    version: PageConfig.getOption('appVersion') || 'unknown',
    devMode: PageConfig.getOption('devMode').toLowerCase() === 'true',
    deferred: { patterns: [], matches: [] },
    disabled: { patterns: [], matches: [] },
    mimeExtensions: [],
    urls: {
      base: PageConfig.getOption('baseUrl'),
      page: PageConfig.getOption('pageUrl'),
      public: PageConfig.getOption('publicUrl'),
      settings: PageConfig.getOption('settingsUrl'),
      themes: PageConfig.getOption('themesUrl'),
      tree: PageConfig.getOption('treeUrl'),
      workspaces: PageConfig.getOption('workspacesUrl')
    },
    directories: {
      appSettings: PageConfig.getOption('appSettingsDir'),
      schemas: PageConfig.getOption('schemasDir'),
      static: PageConfig.getOption('staticDir'),
      templates: PageConfig.getOption('templatesDir'),
      themes: PageConfig.getOption('themesDir'),
      userSettings: PageConfig.getOption('userSettingsDir'),
      serverRoot: PageConfig.getOption('serverRoot'),
      workspaces: PageConfig.getOption('workspacesDir')

devMode: PageConfig.getOption('devMode').toLowerCase() === 'true',
    deferred: { patterns: [], matches: [] },
    disabled: { patterns: [], matches: [] },
    mimeExtensions: [],
    urls: {
      base: PageConfig.getOption('baseUrl'),
      page: PageConfig.getOption('pageUrl'),
      public: PageConfig.getOption('publicUrl'),
      settings: PageConfig.getOption('settingsUrl'),
      themes: PageConfig.getOption('themesUrl'),
      tree: PageConfig.getOption('treeUrl'),
      workspaces: PageConfig.getOption('workspacesUrl')
    },
    directories: {
      appSettings: PageConfig.getOption('appSettingsDir'),
      schemas: PageConfig.getOption('schemasDir'),
      static: PageConfig.getOption('staticDir'),
      templates: PageConfig.getOption('templatesDir'),
      themes: PageConfig.getOption('themesDir'),
      userSettings: PageConfig.getOption('userSettingsDir'),
      serverRoot: PageConfig.getOption('serverRoot'),
      workspaces: PageConfig.getOption('workspacesDir')
    },
    filesCached: PageConfig.getOption('cacheFiles').toLowerCase() === 'true',
    workspace: '',
    defaultWorkspace: ''
  };

  /**
   * The interface for a module that exports a plugin or plugins as
   * the default value.
   */

private _setupLab() {
        let version : string = PageConfig.getOption('appVersion') || 'unknown';
        if (version[0] === 'v') {
            version = version.slice(1);
        }

        if (this.props.options.platform === 'win32') {
            PageConfig.setOption('terminalsAvailable', 'false');
        }

        this._lab = new ElectronJupyterLab({
            version: version,
            mimeExtensions: extensions.mime,
            disabled: extensions.disabled,
            deferred: extensions.deferred,
            platform: this.props.options.platform,
            uiState: this.props.options.uiState
        });

get shouldCheck(): boolean {
    return PageConfig.getOption('buildCheck').toLowerCase() === 'true';
  }

*/
  export const defaultPaths: JupyterFrontEnd.IPaths = {
    urls: {
      base: PageConfig.getOption('baseUrl'),
      defaultWorkspace: PageConfig.getOption('defaultWorkspace'),
      notFound: PageConfig.getOption('notFoundUrl'),
      page: PageConfig.getOption('pageUrl'),
      public: PageConfig.getOption('publicUrl'),
      settings: PageConfig.getOption('settingsUrl'),
      themes: PageConfig.getOption('themesUrl'),
      tree: PageConfig.getOption('treeUrl'),
      workspaces: PageConfig.getOption('workspacesUrl')
    },
    directories: {
      appSettings: PageConfig.getOption('appSettingsDir'),
      schemas: PageConfig.getOption('schemasDir'),
      static: PageConfig.getOption('staticDir'),
      templates: PageConfig.getOption('templatesDir'),
      themes: PageConfig.getOption('themesDir'),
      userSettings: PageConfig.getOption('userSettingsDir'),
      serverRoot: PageConfig.getOption('serverRoot'),
      workspaces: PageConfig.getOption('workspacesDir')
    }
  };

  /**
   * The interface for a module that exports a plugin or plugins as
   * the default value.
   */
  export interface IPluginModule {
    /**
     * The default export.

disabled: { patterns: [], matches: [] },
    mimeExtensions: [],
    filesCached: PageConfig.getOption('cacheFiles').toLowerCase() === 'true'
  };

  /**
   * The default JupyterLab application paths.
   */
  export const defaultPaths: JupyterFrontEnd.IPaths = {
    urls: {
      base: PageConfig.getOption('baseUrl'),
      notFound: PageConfig.getOption('notFoundUrl'),
      app: PageConfig.getOption('appUrl'),
      static: PageConfig.getOption('staticUrl'),
      settings: PageConfig.getOption('settingsUrl'),
      themes: PageConfig.getOption('themesUrl'),
      tree: PageConfig.getOption('treeUrl'),
      workspaces: PageConfig.getOption('workspacesUrl'),
      hubHost: PageConfig.getOption('hubHost') || undefined,
      hubPrefix: PageConfig.getOption('hubPrefix') || undefined,
      hubUser: PageConfig.getOption('hubUser') || undefined,
      hubServerName: PageConfig.getOption('hubServerName') || undefined
    },
    directories: {
      appSettings: PageConfig.getOption('appSettingsDir'),
      schemas: PageConfig.getOption('schemasDir'),
      static: PageConfig.getOption('staticDir'),
      templates: PageConfig.getOption('templatesDir'),
      themes: PageConfig.getOption('themesDir'),
      userSettings: PageConfig.getOption('userSettingsDir'),
      serverRoot: PageConfig.getOption('serverRoot'),
      workspaces: PageConfig.getOption('workspacesDir')