How to use the sigal.signals function in sigal

root_path = self.path if self.path != '.' else ''
                if albums_sort_attr.startswith("meta."):
                    meta_key = albums_sort_attr.split(".", 1)[1]
                    key = lambda s: locale.strxfrm(
                        self.gallery.albums[join(root_path, s)].meta.get(meta_key, [''])[0])
                else:
                    key = lambda s: locale.strxfrm(
                        getattr(self.gallery.albums[join(root_path, s)],
                                albums_sort_attr))
            else:
                key = locale.strxfrm

            self.subdirs.sort(key=key,
                              reverse=self.settings['albums_sort_reverse'])

        signals.albums_sorted.send(self)