provide a clean method for Document

[wpjunior]

In django:
https://docs.djangoproject.com/en/dev/ref/models/instances/?from=olddocs#django.db.models.Model.clean

https://github.com/django/django/blob/stable/1.4.x/django/db/models/base.py#L617
https://github.com/django/django/blob/stable/1.4.x/django/db/models/base.py#L809

example:

class Person(Document):
    name = StringField()
    status = StringField()
    partner = ReferenceField()

    def clean(self):
        if self.status == 'married' and not self.partner:
            raise ValidationError("Partner is missing", field_name="partner")
        elif self.status == 'single':
            self.partner = None

[rozza]

And when would that get called? in to_mongo?

[wpjunior]

in validate():

try:
    self.clean()
except ValidationError, e:
    errors = e.update_error_dict(errors)

[rozza]

In 0.8 - thanks for the code in #66 @wpjunior