Whitespace normalization.
diff --git a/Lib/test/test_mailbox.py b/Lib/test/test_mailbox.py
index e17de5d..474354f 100644
--- a/Lib/test/test_mailbox.py
+++ b/Lib/test/test_mailbox.py
@@ -738,12 +738,12 @@
         time.sleep(0.5)
         self.assertRaises(mailbox.ExternalClashError,
                           self._box.lock)
-        
+
         # Wait for child to exit.  Locking should now succeed.
         exited_pid, status = os.waitpid(pid, 0)
         self._box.lock()
         self._box.unlock()
-        
+
 
 class TestMbox(_TestMboxMMDF):