一个model在admin中多次register

class PostAdmin(admin.ModelAdmin):    list_display = ('title', 'pubdate','user')class MyPosts(Post):    class Meta:        proxy = Trueclass MyPostAdmin(PostAdmin):    def queryset(self, request):        return self.model.objects.filter(user = request.user)admin.site.register(Post, PostAdmin)admin.site.register(MyPost, MyPostAdmin)