I'm going to try to de-emphasize codes (as in secret codes, cryptography). Our main objective is to learn about strings—sequences of characters. Codes are here as an example of an application of string processing. In the past, students have gotten bewildered about codes and failed to grasp strings thoroughly. Still, I hope we do pick up some concepts about codes as well.
Also, I'm going to consider introducing here the new Python string formatting methods, and some learning objectives about code style and management of complexity.