diff --git a/addons/calendar/calendar.py b/addons/calendar/calendar.py
index ce4239783b7..0ee049c1a8e 100644
--- a/addons/calendar/calendar.py
+++ b/addons/calendar/calendar.py
@@ -25,6 +25,7 @@ import re
 import time
 import openerp
 import openerp.service.report
+import uuid
 from datetime import datetime, timedelta
 from dateutil import parser
 from dateutil import rrule