Deprecated since version 2.3: The email package should be used
in preference to the rfc822 module. This module is present only
to maintain backward compatibility, and has been removed in 3.0.
This module defines a class, Message, which represents an “email
message” as defined by the Internet standard RFC 2822.  Such
messages consist of a collection of message headers, and a
message body. This module also defines a helper class
AddressList for parsing RFC 2822 addresses. Please refer to the
RFC for information on the specific syntax of RFC 2822 messages.
The mailbox module provides classes to read mailboxes produced
by various end-user mail programs. class class
rfc822.Message(file[, seekable]) A Message instance is
instantiated with an input object as parameter. Message relies
only on the input object having a readline() method; in
particular, ordinary file objects qualify. Instantiation reads
headers from the input object up to a delimiter line (normally a
blank line) and stores them in the instance. The mes