diff --git a/mayan/apps/acls/classes.py b/mayan/apps/acls/classes.py
index f730a8da60..60acb4bbfa 100644
--- a/mayan/apps/acls/classes.py
+++ b/mayan/apps/acls/classes.py
@@ -36,7 +36,7 @@ class ModelPermission(object):
 
         if as_content_type:
             content_type_dictionary = ContentType.objects.get_for_models(
-                models=cls._registry.keys()
+                *cls._registry.keys()
             )
             content_type_ids = [
                 content_type.pk for content_type in content_type_dictionary.values()
diff --git a/mayan/apps/acls/tests/test_classes.py b/mayan/apps/acls/tests/test_classes.py
new file mode 100644
index 0000000000..483f0feb57
--- /dev/null
+++ b/mayan/apps/acls/tests/test_classes.py
@@ -0,0 +1,12 @@
+from __future__ import absolute_import, unicode_literals
+
+from mayan.apps.common.tests import BaseTestCase
+
+from ..classes import ModelPermission
+
+
+class ModelpermissionTestCase(BaseTestCase):
+    def test_model_permission_get_classes_as_content_type(self):
+        self.assertNotEqual(
+            ModelPermission.get_classes(as_content_type=True).count(), 0
+        )