Python 3 Compatibility

For the project to be future proof, it should be compatible with Py3k. If possible this should be done in a manner which does not break backwards compatibility with Python 2.7 but if necessary a new module/branch should be created.

Metaclass: http://packages.python.org/six/#six.with_metaclass

Django codebase (django.db.models.base.Model):

class Model(six.with_metaclass(ModelBase, object)):
    # ...