How to use the cssutils.css.CSSComment function in cssutils

started = False
        stopall = False
        prod = None
        # flag if default S handling should be done
        defaultS = True
        while True:
            try:
                token = tokens.next()
            except StopIteration:
                break
            type_, val, line, col = token

            # default productions
            if type_ == self.types.COMMENT:
                # always append COMMENT
                seq.append(cssutils.css.CSSComment(val),
                           cssutils.css.CSSComment, line, col)
            elif defaultS and type_ == self.types.S:
                # append S (but ignore starting ones)
                if not keepS or not started:
                    continue
                else:
                    seq.append(val, type_, line, col)
#            elif type_ == self.types.ATKEYWORD:
#                # @rule
#                r = cssutils.css.CSSUnknownRule(cssText=val)
#                seq.append(r, type(r), line, col)
            elif type_ == self.types.INVALID:
                # invalidate parse
                wellformed = False
                self._log.error(u'Invalid token: %r' % (token,))
                break

if self.prefs.keepAllProperties:
                # all
                seq = style.seq
            else:
                # only effective ones
                _effective = style.getProperties()
                seq = [item for item in style.seq 
                         if (isinstance(item.value, cssutils.css.Property) 
                             and item.value in _effective)
                         or not isinstance(item.value, cssutils.css.Property)]

            out = []
            for i, item in enumerate(seq):
                typ, val = item.type, item.value
                if isinstance(val, cssutils.css.CSSComment):
                    # CSSComment
                    if self.prefs.keepComments:
                        out.append(val.cssText)
                        out.append(separator)
                elif isinstance(val, cssutils.css.Property):
                    # PropertySimilarNameList
                    if val.cssText:
                        out.append(val.cssText)
                        if not (self.prefs.omitLastSemicolon and i==len(seq)-1):
                            out.append(u';')
                        out.append(separator)
                elif isinstance(val, cssutils.css.CSSUnknownRule):
                    # @rule
                    out.append(val.cssText)
                    out.append(separator)
                else:

# combine +- and following number or other
                    i += 1
                    try:
                        next = seq[i]
                    except IndexError:
                        firstvalue = () # raised later
                        break

                    newval = item.value + next.value
                    newseq.append(newval, next.type,
                                  item.line, item.col)
                    if not firstvalue:
                        firstvalue = (newval, next.type)
                    count += 1

                elif item.type != cssutils.css.CSSComment:
                    newseq.appendItem(item)
                    if not firstvalue:
                        firstvalue = (item.value, item.type)
                    count += 1

                else:
                    newseq.appendItem(item)

                i += 1

            if not firstvalue:
                self._log.error(
                        u'CSSValue: Unknown syntax or no value: %r.' %
                        self._valuestr(cssText))
            else:
                # ok and set

def do_css_CSSFunction(self, cssvalue, valuesOnly=False):
        """Serialize a CSS function value"""
        if not cssvalue:
            return u''
        else:
            out = Out(self)
            for item in cssvalue.seq:
                type_, val = item.type, item.value
                if valuesOnly and type_ == cssutils.css.CSSComment:
                    continue
                out.append(val, type_)
            return out.value()

def COMMENT(expected, seq, token, tokenizer=None):
            "special: sets parent*"
            self.insertRule(cssutils.css.CSSComment([token],
                            parentStyleSheet=self))
            # or 0 for py3
            return max(1, expected or 0)

def COMMENT(expected, seq, token, tokenizer=None):
            "default impl, adds CSSCommentRule if not token == EOF"
            if expected == 'EOF':
                new['wellformed'] = False
                self._log.error(u'Expected EOF but found comment.', token=token)
            seq.append(cssutils.css.CSSComment([token]), 'COMMENT')
            return expected

def COMMENT(expected, seq, token, tokenizer=None):
            "special: sets parent*"
            comment = cssutils.css.CSSComment([token],
                                parentStyleSheet=self.parentStyleSheet)
            seq.append(comment)
            return expected

# while no real token is found any S are ignored
        started = False
        prod = None
        # flag if default S handling should be done
        defaultS = True
        while True:
            try:
                token = tokens.next()
            except StopIteration:
                break
            type_, val, line, col = token
            
            # default productions
            if type_ == self.types.COMMENT:
                # always append COMMENT
                seq.append(cssutils.css.CSSComment(val),
                           cssutils.css.CSSComment, line, col)
            elif defaultS and type_ == self.types.S:
                # append S (but ignore starting ones)
                if not keepS or not started:
                    continue
                else:
                    seq.append(val, type_, line, col)
#            elif type_ == self.types.ATKEYWORD:
#                # @rule
#                r = cssutils.css.CSSUnknownRule(cssText=val)
#                seq.append(r, type(r), line, col)
            elif type_ == self.types.INVALID:
                # invalidate parse
                wellformed = False
                self._log.error(u'Invalid token: %r' % (token,))
                break

def COMMENT(expected, seq, token, tokenizer=None):
                    seq.append(cssutils.css.CSSComment([token]))
                    return expected