Merge email package 4.0 from the sandbox, including documentation, test cases,

and NEWS updates.

Lib/email/mime/base.py

@@ -0,0 +1,26 @@
+# Copyright (C) 2001-2006 Python Software Foundation
+# Author: Barry Warsaw
+# Contact: email-sig@python.org
+
+"""Base class for MIME specializations."""
+
+__all__ = ['MIMEBase']
+
+from email import message
+
+
+
+class MIMEBase(message.Message):
+    """Base class for MIME specializations."""
+
+    def __init__(self, _maintype, _subtype, **_params):
+        """This constructor adds a Content-Type: and a MIME-Version: header.
+
+        The Content-Type: header is taken from the _maintype and _subtype
+        arguments.  Additional parameters for this header are taken from the
+        keyword arguments.
+        """
+        message.Message.__init__(self)
+        ctype = '%s/%s' % (_maintype, _subtype)
+        self.add_header('Content-Type', ctype, **_params)
+        self['MIME-Version'] = '1.0'