rfc3156.py 文件源码

def attach(self, payload):
        """
        Add the C{payload} to the current payload list.

        Also prevent from adding payloads with wrong Content-Type and from
        exceeding a maximum of 2 payloads.

        :param payload: The payload to be attached.
        :type payload: email.message.Message
        """
        # second payload's content type must be equal to the protocol
        # parameter given on object creation
        if len(self.get_payload()) == 1:
            if payload.get_content_type() != self.get_param('protocol'):
                raise errors.MultipartConversionError(
                    'Wrong content type %s.' % payload.get_content_type)
        # prevent from adding more payloads
        if len(self._payload) == 2:
            raise errors.MultipartConversionError(
                'Cannot have more than two subparts.')
        MIMEMultipart.attach(self, payload)