如何在django admin中显示上传多个文件的计数？

Question

我可以上传多个文件，但如何在list_display ...

显示多个文件

models.py

class PaperManager(models.Model):
    ...

class PaperFile(models.Model):
  image = models.FileField(upload_to='upload/')
  project = models.ForeignKey(PaperManager)    

admin.py

class PaperFileAdmin(admin.ModelAdmin):
        pass

class ProjectFileInline(admin.StackedInline):
    model = PaperFile
    max_num=10
    extra=0
admin.site.register(PaperFile, PaperFileAdmin)

class PaperAdmin(admin.ModelAdmin):    
    inlines = [ProjectFileInline, ]
    list_display = ('id', ...)
    ...
admin.site.register(PaperManager,PaperAdmin)

由于