How to use new email package to read a mailbox?

[Erno Kuusela]

In article <yu99hef2v370.fsf at europa.research.att.com>, Andrew Koenig
<ark at research.att.com> writes:

| The documentation for the mailbox package says that the default behavior
| of class UnixMailbox is to use rfc822.Message to create messages.
| However, rfc822 is noted as deprecated.

UnixMailbox has an optional factory argument, i think you
can pass email.message_from_file there.

  -- erno