code: def _register(self, defaults=None, **kwargs):
          
          f = lambda: self.update_or_create(defaults=defaults, **kwargs)[0]
          ret = SimpleLazyObject(f)
          self._lazy_entries.append(ret)
          return ret
docs: Fetch (update or create)  an instance, lazily.
  
          We're doing this lazily, so that it becomes possible to define
          custom enums in your code, even before the Django ORM is fully
          initialized.
  
          Domain.objects.SHOPPING = Domain.objects.register(
              ref='shopping',
              name='Webshop')
          Domain.objects.USERS = Domain.objects.register(
              ref='users',
              name='User Accounts')