1 From test Sat Feb 1 00:00:00 2014
2 Content-Type: multipart/mixed; boundary="AAA"
3 From: Mail Delivery Subsystem <xxx@example.com>
6 This is a MIME-encapsulated message
13 Content-Type: message/rfc822
15 From: webmaster@python.org
17 Content-Type: multipart/mixed; boundary="BBB"