diff --git a/Demo/threads/sync.py b/Demo/threads/sync.py
index 1688403..843767a 100644
--- a/Demo/threads/sync.py
+++ b/Demo/threads/sync.py
@@ -418,7 +418,7 @@
         self.nonzero.acquire()
         if self.count == self.maxcount:
             raise ValueError, '.v() tried to raise semaphore count above ' \
-                  'initial value %r' % (maxcount,))
+                  'initial value %r' % self.maxcount
         self.count = self.count + 1
         self.nonzero.signal()
         self.nonzero.release()