Construct many rest-of-world geometries and optionally write to filepath ``fp``.

        ``excluded`` must be a **dictionary** of {"rest-of-world label": ["names", "of", "excluded", "locations"]}``.

def construct_rest_of_worlds(self, excluded, fp=None, use_mp=True, simplify=True):
        """Construct many rest-of-world geometries and optionally write to filepath ``fp``.

        ``excluded`` must be a **dictionary** of {"rest-of-world label": ["names", "of", "excluded", "locations"]}``."""
        geoms = {}
        raw_data = []
        for key in sorted(excluded):
            locations = excluded[key]
            for location in locations:
                assert location in self.locations, "Can't find location {}".format(location)
            included = self.all_faces.difference(
                {face for loc in locations for face in self.data[loc]}
            )
            raw_data.append((key, self.faces_fp, included))
        if use_mp:
            with Pool(cpu_count() - 1) as pool:
                results = pool.map(_union, raw_data)
            geoms = dict(results)
        else:
            geoms = dict([_union(row) for row in raw_data])
        if simplify:
            geoms = {k: v.simplify(0.05) for k, v in geoms.items()}
        if fp:
            labels = sorted(geoms)
            self.write_geoms_to_file(fp, [geoms[key] for key in labels], labels)
            return fp
        else:
            return geoms