The Message class defines the following methods in addition to the rfc822.Message methods:
content-type header.  This is
a list of strings.  For parameters of the form
"key=value", key is converted to lower case but
value is not.  For example, if the message contains the header
"Content-type: text/html; spam=1; Spam=2; Spam" then
getplist() will return the Python list ['spam=1',
'spam=2', 'Spam'].
<...>' or `"..."', these are removed.
content-transfer-encoding
message header.  If no such header exists, return '7bit'.  The
encoding is converted to lower case.
content-type header.  If no such header
exists, return 'text/plain'.  The type is converted to lower
case.
content-type header.
If no such header exists, return 'text'.  The main type is
converted to lower case.
content-type header.  If
no such header exists, return 'plain'.  The subtype is
converted to lower case.