def set_charset(self, charset):
        """Set the charset of the payload to a given character set.

        charset can be a Charset instance, a string naming a character set, or
        None.  If it is a string it will be converted to a Charset instance.
        If charset is None, the charset parameter will be removed from the
        Content-Type field.  Anything else will generate a TypeError.

        The message will be assumed to be of type text/* encoded with
        charset.input_charset.  It will be converted to charset.output_charset
        and encoded properly, if needed, when generating the plain text
        representation of the message.  MIME headers (MIME-Version,
        Content-Type, Content-Transfer-Encoding) will be added as needed.

        """
        if charset is None:
            self.del_param('charset')
            self._charset = None
            return
        if isinstance(charset, basestring):
            charset = email.charset.Charset(charset)
        if not isinstance(charset, email.charset.Charset):
            raise TypeError(charset)
        # BAW: should we accept strings that can serve as arguments to the
        # Charset constructor?
        self._charset = charset
        if not self.has_key('MIME-Version'):
            self.add_header('MIME-Version', '1.0')
        if not self.has_key('Content-Type'):
            self.add_header('Content-Type', 'text/plain',
                            charset=charset.get_output_charset())
        else:
            self.set_param('charset', charset.get_output_charset())
        if str(charset) <> charset.get_output_charset():
            self._payload = charset.body_encode(self._payload)
        if not self.has_key('Content-Transfer-Encoding'):
            cte = charset.get_body_encoding()
            try:
                cte(self)
            except __HOLE__:
                self._payload = charset.body_encode(self._payload)
                self.add_header('Content-Transfer-Encoding', cte)
dataset/ETHPy150Open babble/babble/include/jython/Lib/email/message.py/Message.set_charset