=== modified file 'mandos'
--- mandos	2015-05-31 15:29:22 +0000
+++ mandos	2015-05-31 15:56:58 +0000
@@ -1672,7 +1672,7 @@
         self._pipe = child_pipe
         self._pipe.send(('init', fpr, address))
         if not self._pipe.recv():
-            raise KeyError()
+            raise KeyError(fpr)
     
     def __getattribute__(self, name):
         if name == '_pipe':
@@ -2254,7 +2254,8 @@
                 break
         else:
             # No currently valid tokens were found
-            raise ValueError("Invalid RFC 3339 duration")
+            raise ValueError("Invalid RFC 3339 duration: {!r}"
+                             .format(duration))
     # End token found
     return value