从Python访问maildir收件箱

Question

如何在Python中访问maildir顶层文件夹中的消息？在

顶层文件夹在list_folders()中没有显示iup，迭代这些消息会给我所有文件夹中的消息，这是我不想要的。在

import mailbox
import os
dirpath = os.path.join(os.environ['HOME'], 'Maildir')
mbox = mailbox.Maildir(dirpath, create=False)

print(mbox.list_folders())    # Top-level folder does not show up
folder = mbox.get_folder(???) # What do I put here?
for msg in folder.itervalues():
    ...