... doc string, if it exists, must be the first thing defined in a function (that is, the first thing after the colon). You don't technically need to give your function a doc string, but you ... sys.path is a list of directory names that constitute the current search path. (Yours will look different, depending on your operating system, what version of Python you're running, and where ... test your modules as you write them. Here's an example that uses the if __name__ trick. if __name__ == "__main__": Some quick observations before you get to the good stuff. First, ...