How to use the @swim/view.PopoverView function in @swim/view

protected onMarkerClick(event: MouseEvent): void {
    event.stopPropagation();
    if (!this._popoverView) {
      this._popoverView = new PopoverView();
      const popoverViewController = new IntersectionPopoverViewController(this._info, this._nodeRef);
      this._popoverView.setViewController(popoverViewController);
      this._popoverView.setSource(this.getChildView("marker"));
      this._popoverView.hidePopover();
    }
    this.appView!.togglePopover(this._popoverView, {multi: event.altKey});
  }

protected onClick(event: MouseEvent): void {
    event.stopPropagation();
    if (!this._popoverView) {
      this._popoverView = new PopoverView();
      const popoverViewController = new VehiclePopoverViewController(this._info, this._nodeRef);
      this._popoverView.setViewController(popoverViewController);
      this._popoverView.setSource(this._view!);
      this._popoverView.hidePopover();
    }
    this.appView!.togglePopover(this._popoverView, {multi: event.altKey});
  }
}

protected onMarkerClick(event: MouseEvent): void {
    event.stopPropagation();
    if (!this._popoverView) {
      this._popoverView = new PopoverView();
      const popoverViewController = new AgencyPopoverViewController(this._info, this._nodeRef);
      this._popoverView.setViewController(popoverViewController);
      this._popoverView.hidePopover();
    }
    this._popoverView.setSource(this.getChildView("marker"));
    this.appView!.togglePopover(this._popoverView, {multi: event.altKey});
  }