* @param string $id Importer tag. Used to uniquely identify importer.
* @param string $name Importer name and title.
* @param string $description Importer description.
- * @param callback $callback Callback to run.
+ * @param callable $callback Callback to run.
* @return WP_Error Returns WP_Error when $callback is WP_Error.
*/
function register_importer( $id, $name, $description, $callback ) {