From 3090adac04d75020b9e89698ac7f29f1a31cdc1b Mon Sep 17 00:00:00 2001
From: Ross Lawley <ross.lawley@gmail.com>
Date: Mon, 24 Sep 2012 11:37:54 +0000
Subject: [PATCH] Fixed objectId for DBRef

---
 mongoengine/fields.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mongoengine/fields.py b/mongoengine/fields.py
index 12cc7f2a..7729444e 100644
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -770,7 +770,7 @@ class ReferenceField(BaseField):
     def to_mongo(self, document):
         if isinstance(document, DBRef):
             if not self.dbref:
-                return "%s" % DBRef.id
+                return DBRef.id
             return document
         elif not self.dbref and isinstance(document, basestring):
             return document