diff --git a/schema.py b/schema.py
index 302b9c57ddec56ca3c1c710eb466b752870ed988_c2NoZW1hLnB5..414aed157eb2b1d8d5f3c60032d3e5df4325d583_c2NoZW1hLnB5 100644
--- a/schema.py
+++ b/schema.py
@@ -1,3 +1,4 @@
+from yams.buildobjs import EntityType, String, SubjectRelation
 from cubicweb.schema import format_constraint
 
 class Blog(EntityType):