Python 3.1.3 open mbox file, really slow compared to python 2.x?

I tried in python 3.1.3 to open an mbox file, with the mailbox module. There are only 3 mails in it and it is only 27k big.

But when reading the mails my CPU uses 100% for about 2-3 minutes, until it completes it task without an error.

I tried the same with python 2.7.1 and it takes only about 1-2 seconds?!

Did I found ah bug or I'm doing something wrong? I also tested this on windows and linux, same results :(.

Here's the code I used,开发者_Go百科 from the docs:

import mailbox
for message in mailbox.mbox('~/mbox'):
    subject = message['subject']       # Could possibly be None.
    if subject and 'python' in subject.lower():
        print(subject)

Yes, it's a bug. http://bugs.python.org/issue9124