Django pre_save信号：检查实例是否创建未更新，kwargs ['created']（仍然）存在吗？

I am using Django's pre_save signal to implement auto_now_add. There is a lot of discussion on the internet on why you should or shouldn't implement it yourself. I do not appreciate comments on this. Neither on whether I should be rewriting the save function (I have a lot of models that use auto_now_add so using signals makes sense).I am using Django's pre_save signal to implemen