[Python] Parsing email with Python

I'm writing a Python script to process emails returned from Procmail. As suggested in this question, I'm using the following Procmail config:

:0:
|$HOME/process_mail.py


My process_mail.py script is receiving an email via stdin like this:

From hostname Tue Jun 15 21:43:30 2010
Received: (qmail 8580 invoked from network); 15 Jun 2010 21:43:22 -0400
Received: from mail-fx0-f44.google.com (209.85.161.44)
by ip-73-187-35-131.ip.secureserver.net with SMTP; 15 Jun 2010 21:43:22 -0400
Received: by fxm19 with SMTP id 19so170709fxm.3
for <username@domain.com>; Tue, 15 Jun 2010 18:47:33 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.103.84.1 with SMTP id m1mr2774225mul.26.1276652853684; Tue, 15
Jun 2010 18:47:33 -0700 (PDT)
Received: by 10.123.143.4 with HTTP; Tue, 15 Jun 2010 18:47:33 -0700 (PDT)
Date: Tue, 15 Jun 2010 20:47:33 -0500
Message-ID: <AANLkTikFsIjJ3KYW1HJWcAqQlGXNiXE2YMzrj39I0tdB@mail.gmail.com>
Subject: TEST 12
From: Full Name <username@sender.com>
To: username@domain.com
Content-Type: text/plain; charset=ISO-8859-1

ONE
TWO
THREE


I'm trying to parse the message in this way:

>>> import email
>>> msg = email.message_from_string(full_message)


I want to get message fields like 'From', 'To' and 'Subject'. However, the message object does not contain any of these fields.

What am I doing wrong?

Continue reading...