覆盖保存（）时出现（django）错误 - 姓名＆＃39; self＆＃39;未定义

Question

我试图覆盖我的模型的方法save() ：

class Article(models.Model):
  number = models.PositiveIntegerField(editable=False)

  def save(self, *args, **kwargs):
    if not self.pk: #means: if objects wasn't saved before
      self.number = Article.objects.count() +1 #number is 1-based
    super(Article, self).save(*args, **kwargs)

现在我尝试从管理页面添加新文章。我得到的错误：

self.number = Article.objects.count() +1
NameError: name 'self' is not defined

我做错了什么？

一些可选信息：

• number是某种ID，以我的方式订购对象，但这些ID不应手动更改
• number不允许为空或空白，因此我必须在第一次保存之前设置一个值（这是我尝试使用该代码段的内容）
• 保存对象时，默认number应等于所有对象的数量（保存后），基于1的计数
• 更改将使用管理操作的对象的顺序

整个追溯

追踪（最近一次呼叫最后一次）：

  File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/exception.py", line 39, in inner
    response = get_response(request)
  File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/options.py", line 544, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/decorators.py", line 149, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/views/decorators/cache.py", line 57, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/sites.py", line 211, in inner
    return view(request, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/options.py", line 1509, in add_view
    return self.changeform_view(request, None, form_url, extra_context)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/decorators.py", line 67, in _wrapper
    return bound_func(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/decorators.py", line 149, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/decorators.py", line 63, in bound_func
    return func.__get__(self, type(self))(*args2, **kwargs2)
  File "/usr/lib/python3.5/contextlib.py", line 30, in inner
    return func(*args, **kwds)
  File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/options.py", line 1449, in changeform_view
    self.save_model(request, new_object, form, not add)
  File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/options.py", line 1007, in save_model
    obj.save()
  File "/media/[directory to my projects]/projects_actual/myproject/myapp/models.py", line 69, in save
    seĺf.number = Article.objects.count() + 1
NameError: name 'seĺf' is not defined
[16/Apr/2017 11:07:00] "POST /admin/myapp/article/add/ HTTP/1.1" 500 121043

你错过了一些信息吗？