How to use the genshi.core.Attrs function in Genshi

yield ENTER, event
                    depth = 1
                    while depth > 0:
                        mark, subevent = next()
                        if subevent[0] is START:
                            depth += 1
                        elif subevent[0] is END:
                            depth -= 1
                        if depth == 0:
                            yield EXIT, subevent
                        else:
                            yield INSIDE, subevent
                        test(subevent, namespaces, variables, updateonly=True)
                else:
                    yield OUTSIDE, event
            elif isinstance(result, Attrs):
                # XXX  Selected *attributes* are given a "kind" of None to
                # indicate they are not really part of the stream.
                yield ATTR, (ATTR, (QName(event[1][0] + '@*'), result), event[2])
                yield None, event
            elif isinstance(result, tuple):
                yield OUTSIDE, result
            elif result:
                # XXX Assume everything else is "text"?
                yield None, (TEXT, unicode(result), (None, -1, -1))
            else:
                yield None, event

new_attrs = []
                for name, substream in attrs:
                    if isinstance(substream, basestring):
                        value = substream
                    else:
                        values = []
                        for subkind, subdata, subpos in self._eval(substream,
                                                                   ctxt,
                                                                   **vars):
                            if subkind is TEXT:
                                values.append(subdata)
                        value = [x for x in values if x is not None]
                        if not value:
                            continue
                    new_attrs.append((name, u''.join(value)))
                yield kind, (tag, Attrs(new_attrs)), pos

            elif kind is EXPR:
                result = _eval_expr(data, ctxt, **vars)
                if result is not None:
                    # First check for a string, otherwise the iterable test
                    # below succeeds, and the string will be chopped up into
                    # individual characters
                    if isinstance(result, basestring):
                        yield TEXT, result, pos
                    elif isinstance(result, (int, float, long)):
                        yield TEXT, number_conv(result), pos
                    elif hasattr(result, '__iter__'):
                        substream = _ensure(result)
                        for filter_ in filters:
                            substream = filter_(substream, ctxt, **vars)
                        for event in substream:

strip = True

                new_attrs = []
                for name, value in attrs:
                    if name.namespace == namespace:
                        cls = factory.get_directive(name.localname)
                        if cls is None:
                            raise BadDirectiveError(name.localname,
                                                    self.filepath, pos[1])
                        if type(value) is list and len(value) == 1:
                            value = value[0][1]
                        directives.append((factory.get_directive_index(cls),
                                           cls, value, ns_prefix.copy(), pos))
                    else:
                        new_attrs.append((name, value))
                new_attrs = Attrs(new_attrs)

                if directives:
                    directives.sort()
                    dirmap[(depth, tag)] = (directives, len(new_stream),
                                            strip)

                new_stream.append((kind, (tag, new_attrs), pos))
                depth += 1

            elif kind is END:
                depth -= 1
                new_stream.append((kind, data, pos))

                # If there have have directive attributes with the
                # corresponding start tag, move the events inbetween into
                # a "subprogram"

"""
    text = []
    for token in walker:
        type = token["type"]
        if type in ("Characters", "SpaceCharacters"):
            text.append(token["data"])
        elif text:
            yield TEXT, "".join(text), (None, -1, -1)
            text = []

        if type in ("StartTag", "EmptyTag"):
            if token["namespace"]:
                name = "{%s}%s" % (token["namespace"], token["name"])
            else:
                name = token["name"]
            attrs = Attrs([(QName("{%s}%s" % attr if attr[0] is not None else attr[1]), value)
                           for attr, value in token["data"].items()])
            yield (START, (QName(name), attrs), (None, -1, -1))
            if type == "EmptyTag":
                type = "EndTag"

        if type == "EndTag":
            if token["namespace"]:
                name = "{%s}%s" % (token["namespace"], token["name"])
            else:
                name = token["name"]

            yield END, QName(name), (None, -1, -1)

        elif type == "Comment":
            yield COMMENT, token["data"], (None, -1, -1)

"""
    text = []
    for token in walker:
        type = token["type"]
        if type in ("Characters", "SpaceCharacters"):
            text.append(token["data"])
        elif text:
            yield TEXT, "".join(text), (None, -1, -1)
            text = []

        if type in ("StartTag", "EmptyTag"):
            if token["namespace"]:
                name = "{%s}%s" % (token["namespace"], token["name"])
            else:
                name = token["name"]
            attrs = Attrs([(QName("{%s}%s" % attr if attr[0] is not None else attr[1]), value)
                           for attr, value in token["data"].items()])
            yield (START, (QName(name), attrs), (None, -1, -1))
            if type == "EmptyTag":
                type = "EndTag"

        if type == "EndTag":
            if token["namespace"]:
                name = "{%s}%s" % (token["namespace"], token["name"])
            else:
                name = token["name"]

            yield END, QName(name), (None, -1, -1)

        elif type == "Comment":
            yield COMMENT, token["data"], (None, -1, -1)

def __call__(self, kind, data, pos, namespaces, variables):
        namespace = Namespace(namespaces.get(self.prefix))
        if kind is START:
            if self.principal_type is ATTRIBUTE and data[1]:
                return Attrs([(name, value) for name, value in data[1]
                              if name in namespace]) or None
            else:
                return data[0] in namespace
    def __repr__(self):

def _interpolate_attrs(self, stream):
        for kind, data, pos in stream:

            if kind is START:
                # Record any directive attributes in start tags
                tag, attrs = data
                new_attrs = []
                for name, value in attrs:
                    if value:
                        value = list(interpolate(value, self.filepath, pos[1],
                                                 pos[2], lookup=self.lookup))
                        if len(value) == 1 and value[0][0] is TEXT:
                            value = value[0][1]
                    new_attrs.append((name, value))
                data = tag, Attrs(new_attrs)

            yield kind, data, pos

changed = False
                for name, value in attrs:
                    newval = value
                    if extract_text and isinstance(value, basestring):
                        if name in include_attrs:
                            newval = gettext(value)
                    else:
                        newval = list(self(_ensure(value), ctxt,
                            search_text=False)
                        )
                    if newval != value:
                        value = newval
                        changed = True
                    new_attrs.append((name, value))
                if changed:
                    attrs = Attrs(new_attrs)

                yield kind, (tag, attrs), pos

            elif search_text and kind is TEXT:
                text = data.strip()
                if text:
                    data = data.replace(text, unicode(gettext(text)))
                yield kind, data, pos

            elif kind is SUB:
                directives, substream = data
                # If this is an i18n:msg directive, no need to translate text
                # nodes here
                is_msg = filter(None, [isinstance(d, MsgDirective)
                                       for d in directives])
                substream = list(self(substream, ctxt,

def _generate():
            for c, text in self._chunk(tokens):
                if c:
                    attrs = Attrs([(class_, c)])
                    yield START, (span, attrs), pos
                    yield TEXT, text, pos
                    yield END, span, pos
                else:
                    yield TEXT, text, pos
        return Stream(_generate())