diff --git a/agenda/__init__.py b/agenda/__init__.py
index 6ca9505..fbeb73f 100644
--- a/agenda/__init__.py
+++ b/agenda/__init__.py
@@ -11,6 +11,7 @@ from typing import List
 
 import dateutil
 import dateutil.parser
+import dateutil.tz
 import exchange_calendars
 import holidays
 import lxml