Add ModelWithFieldAttributes *before* PolyModel, so that everything does not become a "ModelWithFieldAttributes" in the Datastore. The way PolyModel works, each Model class hierarchy is stored in the Datastore as the class that directly inherited from PolyModel. So, we do not want to insert ModelWithFieldAttributes *after* PolyModel by inheriting *from* PolyModel, or everything would just be a ModelWithFieldAttributes in the Datastore, instead of Person, Work, Group, etc.

"""
Field-like classes that aren't really fields. It's easier to use objects that
have the same attributes as fields sometimes (avoids a lot of special casing).
"""

from django.db.models import fields

class OrderWrt(fields.IntegerField):
    """
    A proxy for the _order database field that is used when
    Meta.order_with_respect_to is specified.
    """
    name = '_order'
    attname = '_order'
    column = '_order'