control multiple XAML file through one code - wpf

Question

I have made 2 XAML files.
The first one is loaded when I open the program and it contains a button.
XAML (WpfApplication4.xaml):
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="WpfApplication4" Height="300" Width="300">
<Grid>
<Button x:Name="Button" Content="Button" HorizontalAlignment="Left" Height="86" Margin="47,68,0,0" VerticalAlignment="Top" Width="184" Click="Button_Click"/>
</Grid>
</Window>
The second XAML (called addon.xaml) contains a button and a list.
XAML (addon.xaml):
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="addon" Height="300" Width="300">
<Grid>
<Button x:Name="Button2" Content="Button" HorizontalAlignment="Left" Height="86" Margin="47,68,0,0" VerticalAlignment="Top" Width="184" Click="Button2_Click"/>
<ListBox HorizontalAlignment="Left" Height="59" Margin="168,177,0,0" VerticalAlignment="Top" Width="81"/>
<Button Content="Button" HorizontalAlignment="Left" Height="13" Margin="242,25,0,0" VerticalAlignment="Top" Width="23"/>
<Label Content="test" HorizontalAlignment="Left" Height="38" Margin="80,25,0,0" VerticalAlignment="Top" Width="99"/>
</Grid>
</Window>
My goal is to switch between the XAML files when I clicked the button in order to switch screens (now it contains only button and list but generally it should be a very different screen than the first one).
The .py looks as following: (EDITED)
import wpf
from System.Windows import Application, Window
class MyWindow(Window):
def __init__(self):
self.ui = wpf.LoadComponent(self, 'WpfApplication4.xaml')
def Button_Click(self, sender, e):
self.ui = wpf.LoadComponent(self, 'addon.xaml')
def Button2_Click(self, sender, e):
self.ui = wpf.LoadComponent(self, 'WpfApplication4.xaml')
if __name__ == '__main__':
Application().Run(MyWindow())
And it manage to switch between the XAML however, when I click button2 to return to the original XAML (WpfApplication4) It says that there is already exists a variable named button (which is obvious because I cant change the button name every time it is clicked)
Is there a way to "delete" the memory of "self" so it wont remember the variables from the first time it was opened?
Could not register named object. Cannot register duplicate name 'Button' in this scope.
Thank you