And that set of things is identified by the sequence of commands that are indented in, this one right here, following the colon but before I get back to the same place in terms of the indentation.

这个集合就是,后面缩进的一系列命令，就是这一块，在冒号后面,但是要,通过缩进。

麻省理工公开课 - 计算机科学及编程导论课程节选

It's just a placeholder that says I don't yet know what I wanna put here but I wanna put something, let me get back to you in just a moment.

它只是一个占位符，告诉电脑,我想在这放一个东西，但是暂时还不知道放什么东西，我先打断一下。

哈佛公开课 - 计算机科学课程节选