:param stream: file like object.

        :param kind: one of following: ``zip``, ``tgz`` or ``tbz2``.

            Default: ``tgz``.

        :param prefix: name of root directory in archive.

            Default is repository name and changeset's raw_id joined with dash

            (``repo-tip.<KIND>``).

        :param subrepos: include subrepos in this archive.

        :raise ImproperArchiveTypeError: If given kind is wrong.

        :raise VcsError: If given stream is None

        """

        allowed_kinds = settings.ARCHIVE_SPECS

        if kind not in allowed_kinds:

            raise ImproperArchiveTypeError('Archive kind not supported use one'

                'of %s' % ' '.join(allowed_kinds))

        if stream is None:

            raise VCSError('You need to pass in a valid stream for filling'

                           ' with archival data')

        if prefix is None:

            prefix = '%s-%s' % (self.repository.name, self.short_id)

        elif prefix.startswith('/'):

            raise VCSError("Prefix cannot start with leading slash")

        elif prefix.strip() == '':

            raise VCSError("Prefix cannot be empty")

        mercurial.archival.archive(self.repository._repo, stream, ascii_bytes(self.raw_id),

                         safe_bytes(kind), prefix=safe_bytes(prefix), subrepos=subrepos)

    def get_nodes(self, path):

        """

        Returns combined ``DirNode`` and ``FileNode`` objects list representing

        state of changeset at the given ``path``. If node at the given ``path``

        is not instance of ``DirNode``, ChangesetError would be raised.

        """

        if self._get_kind(path) != NodeKind.DIR:

            raise ChangesetError("Directory does not exist for revision %s at "

                " '%s'" % (self.revision, path))

        path = self._fix_path(path)

        filenodes = [FileNode(f, changeset=self) for f in self._file_paths

            if os.path.dirname(f) == path]

        dirs = path == '' and '' or [d for d in self._dir_paths

            if d and posixpath.dirname(d) == path]

        dirnodes = [DirNode(d, changeset=self) for d in dirs

            if os.path.dirname(d) == path]

        als = self.repository.alias

        for k, vals in self._extract_submodules().iteritems():

            #vals = url,rev,type

            loc = vals[0]

            cs = vals[1]

            dirnodes.append(SubModuleNode(k, url=loc, changeset=cs,

                                          alias=als))

        nodes = dirnodes + filenodes

        for node in nodes:

            self.nodes[node.path] = node

        nodes.sort()

        return nodes

    def get_node(self, path):

        """

        Returns ``Node`` object from the given ``path``. If there is no node at

        the given ``path``, ``ChangesetError`` would be raised.

        """

        path = self._fix_path(path)

        if path not in self.nodes:

            if path in self._file_paths:

                node = FileNode(path, changeset=self)

            elif path in self._dir_paths or path in self._dir_paths:

                if path == '':

                    node = RootNode(changeset=self)

                else:

                    node = DirNode(path, changeset=self)

            else:

                raise NodeDoesNotExistError("There is no file nor directory "

                    "at the given path: '%s' at revision %s"

                    % (path, self.short_id))

            # cache node

            self.nodes[path] = node

        return self.nodes[path]

    @LazyProperty

    def affected_files(self):

        """

        Gets a fast accessible file changes for given changeset

        """

        return self._ctx.files()

    @property

    def added(self):

        """

        Returns list of added ``FileNode`` objects.

        """

    @property

    def changed(self):

        """

        Returns list of modified ``FileNode`` objects.

        """

    @property

    def removed(self):

        """

        Returns list of removed ``FileNode`` objects.

        """

    @LazyProperty

    def extra(self):

        return self._ctx.extra()