''

def save(self, out, format):

    if (format == 'TopoJSON'):
        topojson.merge(out, self.names, self.config, self.coord)
    elif (format == 'JSON'):
        geojson.merge(out, self.names, self.config, self.coord)
    elif (format == 'PBF'):
        feature_layers = []
        layers = [self.config.layers[name] for name in self.names]
        for layer in layers:
            (width, height) = (layer.dim, layer.dim)
            tile = layer.provider.renderTile(width, height, layer.projection.srs, self.coord)
            if isinstance(tile, EmptyResponse):
                continue
            feature_layers.append({'name': layer.name(), 'features': get_features(tile.dbinfo, tile.query['PBF'])})
        pbf.merge(out, feature_layers, self.coord)
    else:
        raise ValueError(format)
