# Copyright (C) 2002-2006 Python Software Foundation# Author: Barry Warsaw# Contact: email-sig@python.org """Base class for MIME multipart/* type messages.""" __all__ = ['MIMEMultipart'] from email.mime.base import MIMEBase  class MIMEMultipart(MIMEBase):    """Base class for MIME multipart/* type messages."""     def __init__(self, _subtype='mixed', boundary=None, _subparts=None,                 **_params):        """Creates a multipart/* type message.         By default, creates a multipart/mixed message, with proper        Content-Type and MIME-Version headers.         _subtype is the subtype of the multipart content type, defaulting to        `mixed'.         boundary is the multipart boundary string.  By default it is        calculated as needed.         _subparts is a sequence of initial subparts for the payload.  It        must be an iterable object, such as a list.  You can always        attach new subparts to the message by using the attach() method.         Additional parameters for the Content-Type header are taken from the        keyword arguments (or passed into the _params argument).        """        MIMEBase.__init__(self, 'multipart', _subtype, **_params)        if _subparts:            for p in _subparts:                self.attach(p)        if boundary:            self.set_boundary(boundary)