docs: def changelist_view(self, *args, **kwargs):
          """
          Redirect to the add view if no records exist or the change
          view if the singleton instance exists.
          """
          try:
              singleton = self.model.objects.get()
          except self.model.MultipleObjectsReturned:
              return super(SingletonAdmin, self).changelist_view(*args, **kwargs)
          except self.model.DoesNotExist:
              return redirect(admin_url(self.model, "add"))
          return redirect(admin_url(self.model, "change", singleton.id))