code: def get_cookie_domain(self, app: 'Quart') -> Optional[str]:
          
          if app.config['SESSION_COOKIE_DOMAIN'] is not None:
              return app.config['SESSION_COOKIE_DOMAIN']
          elif app.config['SERVER_NAME'] is not None:
              return '.' + app.config['SERVER_NAME'].rsplit(':', 1)[0]
          else:
              return None
docs: Helper method to return the Cookie Domain for the App.