diff --git a/server/lib/Sensor.py b/server/lib/Sensor.py
index 05beca3..7cc22e2 100755
--- a/server/lib/Sensor.py
+++ b/server/lib/Sensor.py
@@ -2,6 +2,7 @@
 # -*-coding:UTF-8 -*
 
 import os
+import sys
 import time
 import uuid
 import redis