更改UIContextualAction的文本大小

Question

如何增加UIContextualAction上的文字大小？这是我的设置方法。

func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
    let action = UIContextualAction(style: .normal, title:  "\u{02606}", handler: { (ac:UIContextualAction, view:UIView, success:(Bool) -> Void) in
        success(true)
    })
    action.backgroundColor = .blue
    return UISwipeActionsConfiguration(actions: [action]) 
}