docs: def check_is_not_created(method):
      """ Make sure the Object does NOT have an id, yet. """
      def check(self, *args, **kwargs):
          if self.id is not None:
              raise AlreadyCreatedError('%s.id %s already exists.' %
                                       (self.__class__.__name__, self.id))
          return method(self, *args, **kwargs)
      return check