diff --git a/21_twitter_bot.py b/21_twitter_bot.py
index dc0327f..0797c80 100755
--- a/21_twitter_bot.py
+++ b/21_twitter_bot.py
@@ -1,4 +1,5 @@
 import tweepy
+import os
 
 # Authentication credentials - dev.twitter.com
 cfg = {