def METHOD_NAME(self, num_parent_objects, num_child_objects):
    if num_parent_objects == 1:
        return _("%(model_name)s '%(object)s' deleted.") % {
            "model_name": capfirst(self.model._meta.verbose_name),
            "object": self.actionable_objects[0],
        }
    else:
        return ngettext(
            "%(count)d %(model_name)s deleted.",
            "%(count)d %(model_name)s deleted.",
            num_parent_objects,
        ) % {
            "model_name": capfirst(self.model._meta.verbose_name_plural),
            "count": num_parent_objects,
        }