human
I wrote the below code

    out = StringIO('')
    message_context = None
    intrans = False
    inplural = False
    trimmed = False
    singular = []
    plural = []
    incomment = False
    comment = []
    lineno_comment_map = {}
    comment_lineno_cache = None
    raw_prefix = 'u'
    def join_tokens(tokens, trim=False):
        message = ''.join(tokens)
        if trim:
            message = trim_whitespace(message)
        return message
    for t in Lexer(src).tokenize():
        if incomment:
            if ((t.token_type == TOKEN_BLOCK) and (t.contents == 'endcomment')):
                content = ''.join(comment)
                translators_comment_start = None
                for (lineno, line) in enumerate(content.splitlines(True)):
                    if line.lstrip().startswith(TRANSLATOR_COMMENT_MARK):
                        translators_comment_start = lineno
                for (lineno, line) in enumerate(content.splitlines(True)):
                    if ((translators_comment_start is not None) and (lineno >= translators_comment_start)):
                        out.write(('    #    %s' % line))
                    else:
                        out.write('    #\n')
                incomment = False
                comment = []
            else:
                comment.append(t.contents)
        elif intrans:
            if (t.token_type == TOKEN_BLOCK):
                endbmatch = endblock_re.match(t.contents)
                pluralmatch = plural_re.match(t.contents)
                if endbmatch:
                    if inplural:
                        if message_context:
                            out.write('    npgettext({p}{!r},    {p}{!r},    {p}{!r},count)    '.format(message_context, join_tokens(singular, trimmed), join_tokens(plural, trimmed), p=raw_prefix))
                        else:
                            out.write('    ngettext({p}{!r},    {p}{!r},    count)    '.format(join_tokens(singular, trimmed), join_tokens(plural, trimmed), p=raw_prefix))
                        for part in singular:
     ...

What's a good function header?
 Give me a Python code to fix = 'u'?
assistant
#Here is Python code to fix = 'u'
.

def templatize(src, origin=None):