code: def stop(self):
          
          super(AggregateDependency, self).stop()
  
          if self.services:
              return [
                  (service, reference)
                  for reference, service in self.services.items()
              ]
  
          return None
docs: Stops the dependency manager (must be called before clear())
  
          :return: The removed bindings (list) or None