How to use the @angular/cdk/a11y.ActiveDescendantKeyManager function in @angular/cdk

public ngAfterContentInit(): void {
    this.keyManager = new ActiveDescendantKeyManager(this.options).withWrap();

    // Set the initial visibility state.
    this.setVisibility();
  }

private _initKeyManager(): void {
    this._keyManager = new ActiveDescendantKeyManager>(this.options)
      .withTypeAhead()
      .withVerticalOrientation()
      .withHorizontalOrientation('ltr');

    this._keyManager.tabOut.pipe(takeUntil(this._destroy)).subscribe(() => {
      // Restore focus to the trigger before closing. Ensures that the focus
      // position won't be lost if the user got focus into the overlay.
      this.focus();
      this.close();
    });

    this._keyManager.change.pipe(takeUntil(this._destroy)).subscribe(() => {
      if (this._panelOpen && this.panel) {
        this._scrollActiveOptionIntoView();
      } else if (!this._panelOpen && this._keyManager.activeItem) {
        this._keyManager.activeItem._selectViaInteraction();

private initKeyManager(): void {
    // We need to initialize with wrapping turned on
    this.keyManager = new ActiveDescendantKeyManager(this.options)
      .withTypeAhead()
      .withVerticalOrientation()
      .withHorizontalOrientation('ltr')
      .withWrap();
  }

private initKeyManager(): void {
    // We need to initialize with wrapping turned on
    this.keyManager = new ActiveDescendantKeyManager(this.options)
      .withTypeAhead()
      .withVerticalOrientation()
      .withHorizontalOrientation('ltr')
      .withWrap();

  }

private _initializeFocusKeyManager() {
        this._keyManager = new ActiveDescendantKeyManager(this.options)
            .withWrap()
            // .withTypeAhead()
            // Allow disabled items to be focusable. For accessibility reasons, there must be a way for
            // screenreader users, that allows reading the different options of the list.
            .skipPredicate(() => false);
    }

function () {
        this._keyManager = new ActiveDescendantKeyManager(this.options).withWrap();
        // Set the initial visibiity state.
        this._setVisibility();
    };
    /**

ngAfterViewInit() {
    this.keyboardEventsManager =
      new ActiveDescendantKeyManager(this.options).withWrap(true);
  }

ngAfterViewInit() {
    this.keyManager = new ActiveDescendantKeyManager(this.items)
      .withWrap()
      .withTypeAhead();
  }

_initKeyManager() {
        this._keyManager = new ActiveDescendantKeyManager(this.options).withTypeAhead();
        this._keyManager.tabOut.pipe(takeUntil(this._destroy)).subscribe(() => this.close());
        this._keyManager.change.pipe(takeUntil(this._destroy)).subscribe(() => {
            if (this._panelOpen && this.panel) {
                this._scrollActiveOptionIntoView();
            }
            else if (!this._panelOpen && !this.multiple && this._keyManager.activeItem) {
                this._keyManager.activeItem._selectViaInteraction();
            }
        });
    }
    /**