User.save() and User.validate()

[Winnetou]

In the mongokit.auth.User class '_id' and 'login' meant to be the same.
In [1]: from mongokit.auth import User
In [2]: me = User()
In [3]: me.login, me.email, me.password = 'Winnetou', 'mieszko.chowaniec@gmail.com', 'supersecret'
In [4]: me
Out [4]:
{'_id': 'Winnetou',
'user': {'email': 'mieszko.chowaniec@gmail.com',
'login': 'Winnetou',
'password': u'24f1ae1bd48d66a899a0929ad94643f4ac3d395276ee5135bacea9ee3f1a2746b2660b2f0421cd3f'}}

In [5]: me.validate()

---

InvalidDocument Traceback (most recent call last)
in ()
--> 1 me.validate()

/usr/local/lib/python2.7/dist-packages/mongokit/document.pyc in validate(self, auto_migrate)
227 # found when validating at init with autorefs
228 self._make_reference(self, self.structure)
--> 229 size = self.get_size()
230 (size_limit, size_limit_str) = self._get_size_limit()
231

/usr/local/lib/python2.7/dist-packages/mongokit/document.pyc in get_size(self)
261 except:
262 self._process_custom_type('bson', self, self.structure)
--> 263 size = len(BSON.encode(self))
264 self._process_custom_type('python', self, self.structure)
265 return size

/usr/local/lib/python2.7/dist-packages/bson/init.pyc in encode(cls, document, check_keys, uuid_subtype)
588 .. versionadded:: 1.9
589 """
--> 590 return cls(_dict_to_bson(document, check_keys, uuid_subtype))
591
592 def decode(self, as_class=dict,

InvalidDocument: Cannot encode object: {'login': 'Winnetou', 'password': u'24f1ae1bd48d66a899a0929ad94643f4ac3d395276ee5135bacea9ee3f1a2746b2660b2f0421cd3f', 'email': 'mieszko.chowaniec@gmail.com'}

In [6]: me.save()

---

InvalidDocument Traceback (most recent call last)
in ()
-->1 me.save()

/usr/local/lib/python2.7/dist-packages/mongokit/auth.py in save(self, _args, *_kwargs)
97 def save(self, _args, *_kwargs):
98 assert self['_id'] == self['user']['login']
---> 99 super(User, self).save(_args, *_kwargs)

/usr/local/lib/python2.7/dist-packages/mongokit/document.pyc in save(self, uuid, validate, safe, _args, *_kwargs)
418 """
419 if validate is True or (validate is None and self.skip_validation is False):
--> 420 self.validate(auto_migrate=False)
421 else:
422 if self.use_autorefs:

/usr/local/lib/python2.7/dist-packages/mongokit/document.pyc in validate(self, auto_migrate)
227 # found when validating at init with autorefs
228 self._make_reference(self, self.structure)
--> 229 size = self.get_size()
230 (size_limit, size_limit_str) = self._get_size_limit()
231

/usr/local/lib/python2.7/dist-packages/mongokit/document.pyc in get_size(self)
261 except:
262 self._process_custom_type('bson', self, self.structure)
--> 263 size = len(BSON.encode(self))
264 self._process_custom_type('python', self, self.structure)
265 return size

/usr/local/lib/python2.7/dist-packages/bson/init.pyc in encode(cls, document, check_keys, uuid_subtype)
588 .. versionadded:: 1.9
589 """
--> 590 return cls(_dict_to_bson(document, check_keys, uuid_subtype))
591
592 def decode(self, as_class=dict,

InvalidDocument: Cannot encode object: {'login': 'Winnetou', 'password': u'24f1ae1bd48d66a899a0929ad94643f4ac3d395276ee5135bacea9ee3f1a2746b2660b2f0421cd3f', 'email': 'mieszko.chowaniec@gmail.com'}

[Winnetou]

Running the test_auth shows the same problem: cannot encode object.
It looks like it was never run before (?).