entity = generic.GenericForeignKey('entity_content_type', 'entity_object_id')
value_content_type = models.ForeignKey(ContentType, related_name='attribute_value_set', limit_choices_to=attribute_value_limiter, verbose_name='Value type', null=True, blank=True)
entity = generic.GenericForeignKey('entity_content_type', 'entity_object_id')
value_content_type = models.ForeignKey(ContentType, related_name='attribute_value_set', limit_choices_to=attribute_value_limiter, verbose_name='Value type', null=True, blank=True)