public function download_solutions($task_set_id)
{
$task_set = new Task_set();
$task_set->get_by_id((int) $task_set_id);
if ($task_set->exists()) {
$task_set->download_all_solutions();
} else {
$this->messages->add_message('lang:admin_solutions_solutions_download_unknown_task_set', Messages::MESSAGE_TYPE_ERROR);
redirect(create_internal_url('admin_solutions'));
}
}