def append(self, s, charset=None, errors='strict'):
        if charset is None:
            charset = self._charset
        elif not isinstance(charset, Charset):
            charset = Charset(charset)
        # If the charset is our faux 8bit charset, leave the string unchanged
        if charset <> '8bit':
            # We need to test that the string can be converted to unicode and
            # back to a byte string, given the input and output codecs of the
            # charset.
            if isinstance(s, str):
                # Possibly raise UnicodeError if the byte string can't be
                # converted to a unicode with the input codec of the charset.
                incodec = charset.input_codec or 'us-ascii'
                ustr = unicode(s, incodec, errors)
                # Now make sure that the unicode could be converted back to a
                # byte string with the output codec, which may be different
                # than the iput coded.  Still, use the original byte string.
                outcodec = charset.output_codec or 'us-ascii'
                ustr.encode(outcodec, errors)
            elif isinstance(s, unicode):
                # Now we have to be sure the unicode string can be converted
                # to a byte string with a reasonable output codec.  We want to
                # use the byte string in the chunk.
                for charset in USASCII, charset, UTF8:
                    try:
                        outcodec = charset.output_codec or 'us-ascii'
                        s = s.encode(outcodec, errors)
                        break
                    except UnicodeError:
                        pass
                else:
                    assert False, 'utf-8 conversion failed'
        self._chunks.append((s, charset))
Append a string to the MIME header.
dataset/ETHPy150Open babble/babble/include/jython/Lib/email/header.py/Header.append