使用Django Abstract Class创建关系并继承该类会出于某种原因创建两个反向关系

This is my model:

这是我的模特：

class Post(models.Model):
    owner = models.ForeignKey(User, related_name="%(app_label)s%(class)s_set")
    post = models.CharField(max_length=400)

    class Meta:
        abstract = True


class DS(Post):
    location = models.ForeignKey(Location, blank=True, null=True, related_name="%(app_label)s%(class)s_set")

    class Meta(Post.Meta):
        abstract = True

class S(DS):
    # same as DS
    pass
class Post(models