So the following stacktraces are related to SQLAlchemy's @hybrid_property and I'm not sure how/if these can be fixed:

/home/ghugo/keystone/doc/source/api/keystone.identity.backends.rst:33: WARNING: autodoc: failed to import attribute u'User.password_created_a
t' from module u'keystone.identity.backends.sql_model'; the following exception was raised:
Traceback (most recent call last):
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/ext/autodoc.py", line 393, in import_object
    obj = self.get_attr(obj, part)
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/ext/autodoc.py", line 289, in get_attr
    return safe_getattr(obj, name, *defargs)
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/util/inspect.py", line 115, in safe_getattr
    raise AttributeError(name)
AttributeError: password_created_at
/home/ghugo/keystone/doc/source/api/keystone.identity.backends.rst:33: WARNING: autodoc: failed to import attribute u'User.password_expires_a
t' from module u'keystone.identity.backends.sql_model'; the following exception was raised:
Traceback (most recent call last):
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/ext/autodoc.py", line 393, in import_object
    obj = self.get_attr(obj, part)
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/ext/autodoc.py", line 289, in get_attr
    return safe_getattr(obj, name, *defargs)
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/util/inspect.py", line 115, in safe_getattr
    raise AttributeError(name)
AttributeError: password_expires_at
/home/ghugo/keystone/doc/source/api/keystone.identity.backends.rst:33: WARNING: autodoc: failed to import attribute u'User.password_is_expired' from module u'keystone.identity.backends.sql_model'; the following exception was raised:
Traceback (most recent call last):
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/ext/autodoc.py", line 393, in import_object
    obj = self.get_attr(obj, part)
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/ext/autodoc.py", line 289, in get_attr
    return safe_getattr(obj, name, *defargs)
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/util/inspect.py", line 115, in safe_getattr
    raise AttributeError(name)
AttributeError: password_is_expired
/home/ghugo/keystone/doc/source/api/keystone.identity.backends.rst:33: WARNING: autodoc: failed to import attribute u'User.password_ref' from module u'keystone.identity.backends.sql_model'; the following exception was raised:
Traceback (most recent call last):
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/ext/autodoc.py", line 393, in import_object
    obj = self.get_attr(obj, part)
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/ext/autodoc.py", line 289, in get_attr
    return safe_getattr(obj, name, *defargs)
  File "/home/ghugo/keystone/.tox/docs/local/lib/python2.7/site-packages/sphinx/util/inspect.py", line 115, in safe_getattr
    raise AttributeError(name)
AttributeError: password_ref