code: def PostUnregistration(method):
      # pylint: disable=C0103
      
      if not isinstance(method, types.FunctionType):
          raise TypeError("@PostUnregistration can only be applied on functions")
  
      # Tests the number of parameters
      validate_method_arity(method, "service_reference")
      _append_object_entry(
          method,
          constants.IPOPO_METHOD_CALLBACKS,
          constants.IPOPO_CALLBACK_POST_UNREGISTRATION,
      )
      return method
docs: The service post-unregistration callback decorator is called after a service
      of the component has been unregistered from the framework.
  
      The decorated method must accept the
      :class:`~pelix.framework.ServiceReference` of the registered
      service as argument::
  
         @PostUnregistration
         def callback_method(self, service_reference):
             '''
             service_reference: The ServiceReference of the provided service
             '''
             # ...
  
      :param method: The decorated method
      :raise TypeError: The decorated element is not a valid function