如何在xamarin窗体的ViewModel类中使用Navigation.InsertPageBefore？

public class MyViewModel : ViewModelBase
{
    private readonly INavigation _navigation;

    public MyViewModel(INavigation navigation)
    {
        _navigation = navigation;
    }

    // 其他代码...
}

public class MyViewModel : ViewModelBase
{
    private readonly INavigation _navigation;

    public MyViewModel(INavigation navigation)
    {
        _navigation = navigation;
    }

    public void InsertPageBefore(Page pageToInsert, Page referencePage)
    {
        _navigation.InsertPageBefore(pageToInsert, referencePage);
    }
}

public partial class MyPage : ContentPage
{
    private readonly MyViewModel _viewModel;

    public MyPage(MyViewModel viewModel)
    {
        InitializeComponent();
        _viewModel = viewModel;
    }

    private void InsertPageBeforeButton_Clicked(object sender, EventArgs e)
    {
        var pageToInsert = new PageToInsert();
        var referencePage = new ReferencePage();

        _viewModel.InsertPageBefore(pageToInsert, referencePage);
    }
}