分享一些有用的python代码片，包含如下内容：

1. Excel遍历密码自动化解密
2. 带进度条下载文件
3. 搜索给定目录下特定格式的文件，支持自定义查找深度
4. 线程池的简单用法

Share some useful python snippets, Include the following content:

1. Automatically decrypt password protected excel files.
2. Download the file with the progress bar.
3. Search specific format files from a given directory, support custom search depth.
4. A demo about thread pool.