Minimal example to subscribe to settings change in xdg-.desktop-portal

xdg-desktop-portal-settings.py

#!/usr/bin/env python3                                                          
                                                                                
from dasbus.connection import SessionMessageBus, SystemMessageBus               
from dasbus.loop import EventLoop                                               
                                                                                
bus = SessionMessageBus()                                                       
loop = EventLoop()                                                              
                                                                                
proxy = bus.get_proxy(                                                          
    "org.freedesktop.portal.Desktop", # service                                 
    "/org/freedesktop/portal/desktop", # obj path                               
    "org.freedesktop.portal.Settings", # interface                              
)                                                                               
                                                                                
def callback(*args):                                                            
    print("The notification: ", *args)                                          
                                                                                
proxy.SettingChanged.connect(callback)                                          
                                                                                
loop.run()