diff --git a/djadmin2/utils.py b/djadmin2/utils.py
index f597882..e7df77c 100644
--- a/djadmin2/utils.py
+++ b/djadmin2/utils.py
@@ -40,9 +40,13 @@ def model_app_label(obj):
     return model_options(obj).app_label    
 
 
-# Taken from the Django core.
-# https://github.com/django/django/blob/1.5.1/django/contrib/admin/util.py#L144
 class NestedObjects(Collector):
+    """
+    This is adopted from the Django core. django-admin2 mandates that code
+    doesn't depend on imports from django.contrib.admin.
+
+    https://github.com/django/django/blob/1.5.1/django/contrib/admin/util.py#L144
+    """
     def __init__(self, *args, **kwargs):
         super(NestedObjects, self).__init__(*args, **kwargs)
         self.edges = {} # {from_instance: [to_instances]}
diff --git a/example/blog/tests/test_nestedobjects.py b/example/blog/tests/test_nestedobjects.py
index c58378f..1501906 100644
--- a/example/blog/tests/test_nestedobjects.py
+++ b/example/blog/tests/test_nestedobjects.py
@@ -6,11 +6,14 @@ from djadmin2.utils import NestedObjects
 from ..models import Count, Event, EventGuide, Guest, Location
 
 
-# Largely taken from the Django core.
-# https://github.com/django/django/blob/1.5.1/tests/regressiontests/admin_util/tests.py
 class NestedObjectsTests(TestCase):
     """
     Tests for ``NestedObject`` utility collection.
+
+    This is adopted from the Django core. django-admin2 mandates that code
+    doesn't depend on imports from django.contrib.admin.
+
+    https://github.com/django/django/blob/1.5.1/tests/regressiontests/admin_util/tests.py
     """
     def setUp(self):
         self.n = NestedObjects(using=DEFAULT_DB_ALIAS)