diff --git a/ifupdown2/ifupdown/scheduler.py b/ifupdown2/ifupdown/scheduler.py
index 154e557..fda6ff2 100644
--- a/ifupdown2/ifupdown/scheduler.py
+++ b/ifupdown2/ifupdown/scheduler.py
@@ -9,6 +9,7 @@
 
 import os
 import sys
+import traceback
 
 from collections import OrderedDict