While fixing the tkinter demos, I found some problems when moving from
mhlib to mailbox that are corrected in the attached patch.

The first fix:

-        for name, key_list in self.get_sequences():
+        for name, key_list in self.get_sequences().iteritems():

I'm not sure someone else used the module before, or at least
get_sequences() since it returns a dict and it just fails in the current
code.

The second fix is about the .mh_sequences file format I found here, it
may have some lines with one space, or two, after its content which was
causing the get_sequences() to fail too.

Erm.. sorry, the first correction is directly related to get_message not
get_sequences per se.

Added a test case

@gpolo: your patch is correct, but I prefer line.rstrip() to 
line.strip(). My new patch combines your two patches + replace strip 
by rstrip + use itervalues() instead of items() in MH.pack().

Ping. Nobody is interested by the patch?

The iteritems problem was fixed in r71046 from issue2625.  The tests in
mailbox.patch all pass at this point, though it doesn't look like the
line with blanks issue has been addressed in the code.

Anyone interested in taking this forward?

self.get_sequences() => self.get_sequences().iteritems() was fixed in trunk (r71046) and py3k (r71067).

The patch on .get_sequences() has no test: (test_get_message_with_sequences() doesn't fail without the patch.