code: def invalidate(self):
          " Invalidate the UI for all clients. "
          logger.info('Invalidating %s applications', len(self.apps))
  
          for app in self.apps:
              app.invalidate(f invalidate(self):
          " Invalidate the UI for all clients. "
          logger.info('Invalidating %s applications', len(self.apps))
  
          for app in self.apps:
              app.invalidate()
docs: Invalidate the UI for all clients.