--- lockfile-0.8/lockfile.py	2009-03-30 12:44:14.000000000 +0200
+++ lockfile/lockfile.py	2012-10-14 14:13:27.000000000 +0200
@@ -259,11 +263,11 @@
                         os.unlink(self.unique_name)
                         if timeout > 0:
                             raise LockTimeout
                         else:
                             raise AlreadyLocked
-                    time.sleep(timeout is not None and timeout/10 or 0.1)
+                    time.sleep(timeout/10. if timeout > 0 else 0.1)
             else:
                 # Link creation succeeded.  We're good to go.
                 return
 
     def release(self):