diff --git a/docs/topics/db/multi-db.txt b/docs/topics/db/multi-db.txt
index 72b5116504..27dc2261ca 100644
--- a/docs/topics/db/multi-db.txt
+++ b/docs/topics/db/multi-db.txt
@@ -256,7 +256,7 @@ master/slave relationship between the databases ``master``, ``slave1`` and
         def allow_relation(self, obj1, obj2, **hints):
             "Allow any relation between two objects in the db pool"
             db_list = ('master','slave1','slave2')
-            if obj1 in db_list and obj2 in db_list:
+            if obj1._state.db in db_list and obj2._state.db in db_list:
                 return True
             return None