mistake in example in /db/managers/ documentation

[aakelm]

The page

​https://docs.djangoproject.com/en/dev/topics/db/managers/

has an example which begins with the line

class ExtraManager(models.Model):

It seems to me that the inheritance there is wrong, and it should be

class ExtraManager(models.Manager):

[Tim Graham]

I don't think so. ExtraManager looks like it's an abstract model used to add a manager to a model.