One difficulty I had with `do` is that its really hard to find in the docs if you don't have any idea what it is. Try googling it or searching for it in the docs, do is just really a common word so there is a lot of interference. Then it sort of looks like an if or while statement, so I tried looking in Control Flow, but its not there.
Also I think open is a particularly confusing (but also useful) example of the do block syntax, since the specific method of open that is called is fairly different from most of the other open methods. Most methods return a file handle, and leave the file open, while this particular method opens and closes the file. So it's sort of a double whammy of potential confusion.
