Barry asked me to open this so as to attach the message.

If the feed parser parsers a message that has a content-type 
of multipart/<something> but which contains only a single 
part, the resulting Message object is internally 
inconsistent: get_main_type() returns "multipart" but 
is_multipart() returns False.

I don't think that this is actually a bug because figuring out 
the right content-type to assign would require groveling 
through the payload with a bunch of messy heuristics. It 
seems to me that the standard library isn't the place for 
messy heuristics.