20 from email import charset as _charset
77         return [(_charset._encode(string, str(charset)), str(charset))
78                     for string, charset in header._chunks]
97                 charset = parts.pop(0).lower()
100                 words.append((encoded, encoding, charset))
114     for encoded_string, encoding, charset in words:
117             decoded_words.append((encoded_string, charset))
120             decoded_words.append((word, charset))
130                 decoded_words.append((word, charset))
137     for word, charset in decoded_words:
142             last_charset = charset
143         elif charset != last_charset:
146             last_charset = charset
170     for s, charset in decoded_seq:
172         if charset is not None and not isinstance(charset, Charset):
173             charset = Charset(charset)
174         h.append(s, charset)
180     def __init__(self, s=None, charset=None,  argument
209         if charset is None:
210             charset = USASCII
211         elif not isinstance(charset, Charset):
212             charset = Charset(charset)
213         self._charset = charset
217             self.append(s, charset, errors)
233         for string, charset in self._chunks:
240             nextcs = charset
265     def append(self, s, charset=None, errors='strict'):  argument
286         if charset is None:
287             charset = self._charset
288         elif not isinstance(charset, Charset):
289             charset = Charset(charset)
291             input_charset = charset.input_codec or 'us-ascii'
298         output_charset = charset.output_codec or 'us-ascii'
305                 charset = UTF8
306         self._chunks.append((s, charset))
358         for string, charset in self._chunks:
362                     if not hasspace or charset not in (None, 'us-ascii'):
364                 elif charset not in (None, 'us-ascii') and not lastspace:
367             lastcs = charset
371                 formatter.feed('', lines[0], charset)
373                 formatter.feed('', '', charset)
376                 if charset.header_encoding is not None:
378                                    charset)
382                     formatter.feed(fws, sline, charset)
399         for string, charset in self._chunks:
400             if charset == last_charset:
406                 last_charset = charset
443     def feed(self, fws, string, charset):  argument
449         if charset.header_encoding is None:
459         encoded_lines = charset.header_encode_lines(string, self._maxlengths())