在python中从Maildir获取所有新消息

foo@foo:~/Maildir$ ls -l
total 288
drwx------ 2 foo foo 155648 2010-04-19 15:19 cur
-rw------- 1 foo foo    440 2010-03-20 08:50 dovecot.index.log
-rw------- 1 foo foo    112 2010-03-20 08:49 dovecot-uidlist
-rw------- 1 foo foo      8 2010-03-20 08:49 dovecot-uidvalidity
-rw------- 1 foo foo      0 2010-03-20 08:49 dovecot-uidvalidity.4ba48c0e
drwx------ 2 foo foo 114688 2010-04-19 16:07 new
drwx------ 2 foo foo   4096 2010-04-19 16:07 tmp

>>> import mailbox
>>> md = mailbox.Maildir('/home/foo/Maildir')
>>> md.iterkeys().next()
'1269924477.Vfc01I4249fM708004.foo'

>>> md = mailbox.Maildir('/home/foo/Maildir/new')
>>> md.iterkeys().next()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.6/mailbox.py", line 346, in iterkeys
    self._refresh()
  File "/usr/lib/python2.6/mailbox.py", line 467, in _refresh
    for entry in os.listdir(subdir_path):
OSError: [Errno 2] No such file or directory: '/home/foo/Maildir/new/new'
>>>