请英语高人帮忙看一句话nobody would have known if you would have kept it

请英语高人帮忙看一句话
nobody would have known if you would have kept it
背景是一个老外捡了一个钱包,里边有5000$,但他上交了,他的一个朋友就说了这句话
我的问题是,按照虚拟语气的说法,他不是应该说if you had kept it,noboday would have known?
而且他这里if you would have kept it 怎么理解呢?
问题是这句话是老外说的啊，美国外教说的...如果native speaker说的都不对，谁说的对？