gistfile1.py

>>> from django.contrib.auth.models import User
>>> u = User.objects.all()[0]
>>> u
<User: preston>
>>> u.natural_key
<bound method User.natural_key of <User: preston>>
>>> u.natural_key()
(u'preston',)
>>> nat_key = u.natural_key()
>>> User.objects.get_by_natural_key(nat_key)
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/Users/preston/Projects/code/forks/django/django/contrib/auth/models.py", line 184, in get_by_natural_key
    return self.get(username=username)
  File "/Users/preston/Projects/code/forks/django/django/db/models/manager.py", line 131, in get
    return self.get_query_set().get(*args, **kwargs)
  File "/Users/preston/Projects/code/forks/django/django/db/models/query.py", line 366, in get
    % self.model._meta.object_name)
DoesNotExist: User matching query does not exist.
>>>