在将WPF与IronPython一起使用时，如何创建“本地”命名空间？

Question

我正在尝试创建一个用于WPF xaml的类型转换器。我确保等效的C#代码工作正常，然后将其移植到IronPython。然而，我仍然坚持在xaml中引用TC类。更具体地说，如何将“本地”命名空间指向IronPython全局命名空间？下面是代码，它没有运行，因为xmlns:local="clr-namespace:global"生成错误

import clr
clr.AddReference("PresentationFramework")
clr.AddReference("PresentationCore")
clr.AddReference("System.Xml")
from System.Xml import XmlReader
from System.IO import StringReader
from System.Windows.Markup import XamlReader
from System.Windows.Data import IValueConverter
from System.Windows import Visibility

class tc(IValueConverter):
    def Convert(value, targetType, parameter, culture):
        if value:
            return Visibility.Visible
        else:
            return Visibility.Collapsed

    def ConvertBack(value, targetType, parameter, culture):
        pass


s = XmlReader.Create(StringReader('''
<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"        
        mc:Ignorable="d"
        xmlns:local="clr-namespace:global"  
        Title="MainWindow" Height="450" Width="800">
    <Window.Resources>
        <local:tc x:Key="tc" />
    </Window.Resources>
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <CheckBox x:Name="checkbox" IsChecked="True" Content="Visible" Grid.Column="0"/>
        <Button Visibility="{Binding ElementName=checkbox, Path=IsChecked, Converter={StaticResource tc}}" Content="Button" Height="20" Grid.Column="1"/>
    </Grid>
</Window>
'''))


win = XamlReader.Load(s)
win.ShowDialog()