diff --git a/steam/guard.py b/steam/guard.py
index 6a78c6f..a5dd744 100644
--- a/steam/guard.py
+++ b/steam/guard.py
@@ -70,7 +70,7 @@ class SteamAuthenticator(object):
 
     def __getattr__(self, key):
         if key not in self.secrets:
-            raise AttributeError("No such attribute")
+            raise AttributeError("No %s attribute" % repr(key))
         return self.secrets[key]
 
     def get_time(self):