Django taggit at Kind of tag by proxy

model-KindTaggedItem.py

# .../apps/taggit-wrap/models.py

from django.db import models
from django.contrib.contenttypes.models import ContentType
from django.utils.translation import ugettext_lazy as _

from taggit.models import GenericTaggedItemBase, TaggedItemBase


# Mixin
class KindTaggedBase(models.Model):
    kind_name = ''
    kind = models.CharField(verbose_name=_('Kind'), max_length=100, null=True)
    
    class Meta:
        abstract = True
    
    @classmethod
    def lookup_kwargs(cls, instance):
        return {
            'object_id': instance.pk,
            'content_type': ContentType.objects.get_for_model(instance),
            'kind' : cls.kind_name
        }

    @classmethod
    def bulk_lookup_kwargs(cls, instances):
        # TODO: instances[0], can we assume there are instances.
        return {
            'object_id__in': [instance.pk for instance in instances],
            'content_type': ContentType.objects.get_for_model(instances[0]),
            'kind' : cls.kind_name
        }

    @classmethod
    def tags_for(cls, model, instance=None):
        ct = ContentType.objects.get_for_model(model)
        kwargs = {
            '%s__content_type' % cls.tag_relname(): ct,
            '%s__kind' % cls.tag_relname() : cls.kind_name
        }
        if instance is not None:
            kwargs['%s__object_id' % cls.tag_relname()] = instance.pk
        return cls.tag_model().objects.filter(**kwargs).distinct()


# Normal Declaration
class KindTaggedItem(KindTaggedBase, GenericTaggedItemBase, TaggedItemBase):
    
    class Meta:
        verbose_name = _("Tagged Item")
        verbose_name_plural = _("Tagged Items")


# 1° Proxy Declaration
class KeywordTaggedItem(KindTaggedItem):
    kind_name = 'keyword'
    
    class Meta:
        verbose_name = _("Keyword Item")
        verbose_name_plural = _("Keyword Items")
        
        proxy = True


# 2° Proxy Declaration
class BadgeTaggedItem(KindTaggedItem):
    kind_name = 'badge'
    
    class Meta:
        verbose_name = _("Badge Item")
        verbose_name_plural = _("Badge Items")
        
        proxy = True

don't work :S
http://pastebin.com/bc9zPPvG
http://pastebin.com/755FF5Ag