> For the complete documentation index, see [llms.txt](https://www.oulan.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.oulan.com/2017/10/23.md). # 23 空以为用，有以为利。早安，世界。早安，未来。早安，无限可能的你。