-from django.db import models
-from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes import generic
+from django.contrib.contenttypes.models import ContentType
+from django.db import models
+from django.template import add_to_builtins as register_templatetags
+
from philo.models.base import value_content_type_limiter, register_value_model
from philo.utils import fattr
-from django.template import add_to_builtins as register_templatetags
class Collection(models.Model):