diff --git a/addons/crm_caldav/crm_caldav.py b/addons/crm_caldav/crm_caldav.py
index 0d46a5429eb..f9e8d0661c1 100644
--- a/addons/crm_caldav/crm_caldav.py
+++ b/addons/crm_caldav/crm_caldav.py
@@ -20,6 +20,7 @@
 ##############################################################################
 
 from osv import fields, osv
+from base_calendar import base_calendar
 from crm import crm
 from caldav import calendar
 from datetime import datetime