DataGrid GroupHeader indent based on level

                    <telerik:RadDataGrid.GroupHeaderTemplate>
                        <DataTemplate x:DataType="gridContext:GroupHeaderContext">
                            <Grid Margin="{Binding Level, Converter={StaticResource GroupHeaderIndentConverter}}">

    public class GroupHeaderIndentConverter : IValueConverter   
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value is int groupLevel)
            {
                return new Thickness(groupLevel * 10, 0, 0, 0);
            }
            return new Thickness(0);
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }