              raise Http404(_('%(name)s object with primary key %(key)r does not exist.') % {'name': force_text(opts.verbose_name), 'key': escape(object_id)})
  
          if request.method == 'POST' and "_saveasnew" in request.POST:
              return self.add_view(request, form_url=reverse('admin:%s_%s_add' %
                                      (opts.app_label, opts.module_name),
                                      current_app=self.admin_site.name))
  
          ModelForm = self.get_form(request, obj)
          formsets = []
          inline_instances = self.get_inline_instances(request, obj)
 
</s> remove                                         (opts.app_label, opts.module_name),
 </s> add                                         (opts.app_label, opts.model_name), </s> remove                                         (opts.app_label, opts.module_name),
 </s> add                                         (opts.app_label, opts.model_name), </s> remove                                         (opts.app_label, opts.module_name),
 </s> add                                         (opts.app_label, opts.model_name), </s> remove         key = (opts.app_label, opts.object_name.lower())
 </s> add         key = (opts.app_label, opts.model_name) </s> remove         if m._meta.object_name.lower() == model_name:
 </s> add         if m._meta.model_name == model_name:
                                    (opts.app_label, opts.model_name),
              raise Http404(_('%(name)s object with primary key %(key)r does not exist.') % {'name': force_text(opts.verbose_name), 'key': escape(object_id)})
  
          if request.method == 'POST' and "_saveasnew" in request.POST:
              return self.add_view(request, form_url=reverse('admin:%s_%s_add' %
                                    (opts.app_label, opts.model_name),
                                      current_app=self.admin_site.name))
  
          ModelForm = self.get_form(request, obj)
          formsets = []
          inline_instances = self.get_inline_instances(request, obj)
keep keep keep keep replace keep keep keep keep keep
 Fixed #19689 -- Renamed `Model._meta.module_name` to `model_name`. 
django/contrib/admin/options.py