@@ -0,0 +1,30 @@
+# This code is supporting material for the book
+# Building Machine Learning Systems with Python
+# by Willi Richert and Luis Pedro Coelho
+# published by PACKT Publishing
+#
+# It is made available under the MIT License
+
+import sys
+
+CONSUMER_KEY = None
+CONSUMER_SECRET = None
+
+ACCESS_TOKEN_KEY = None
+ACCESS_TOKEN_SECRET = None
+
+if CONSUMER_KEY is None or CONSUMER_SECRET is None or ACCESS_TOKEN_KEY is None or ACCESS_TOKEN_SECRET is None:
+    print("""\
+When doing last code sanity checks for the book, Twitter
+was using the API 1.0, which did not require authentication.
+With its switch to version 1.1, this has now changed.
+
+It seems that you don't have already created your personal Twitter
+access keys and tokens. Please do so at
+https://dev.twitter.com/docs/auth/tokens-devtwittercom
+and paste the keys/secrets into twitterauth.py
+
+Sorry for the inconvenience,
+The authors.""")
+
+    sys.exit(1)