Inheritance of Assigned Properties from Mixing

Question

I would like to use the mix-in class to add properties to the model.

from google.appengine.ext import db

class Taggable(object):
    tag_list = db.StringListProperty()

    def attach_tag(self, tag):
        self.tag_list.append(tag)
        self.put()

    def remove_tag(self, tag):
        self.tag_list.pop(self.tag_list.index(tag))
        self.put()

class Post(db.Model, Taggable):
    title = db.TextProperty()

This is just an example, no need to chew on my ear about bad practices or anything else.

Currently, I have something similar to this, except that I have to put tag_list = db.StringListProperty()outside the mix-in (errors otherwise), this is dirty code, and I would like to avoid that.

Just how can I assign properties (like tag_list) to a model from a mix?

Answer 1

Should Taggable be based on db.Model instead of an object?