## Chapter 15 — NOT READY names the false keys ### Learning outcomes After this chapter, you should be able to: 1. Build `missing` as the false keys. 2. Read the printed line as that join. 3. Refuse a count of people inside the Boolean. ### 15.1 One false key. The prose about three accounts is not the value. `missing` keeps every key whose Boolean is false, in dictionary order. `', '.join(missing)` would separate several keys with a comma and a space. This dictionary has one false key, so the join has nothing to separate. The printed line is exactly `NOT READY: admin accounts use MFA`. `READY` prints only when `missing` is empty. It is not empty. The opening week speaks of three administrator accounts. The release lesson says one volunteer administrator has not finished multi-factor sign-in. Those sentences are prose. The Boolean does not store the integer 3, the integer 1, or a fraction. It does not store the volunteer's name, which was never given, or the kind of second factor. Two finished accounts and one unfinished account would be a story about the prose. It is not a value the script computed, and this chapter does not print `2 of 3`. If a second key were false, its name would appear in `missing` in dictionary order, on the same NOT READY line. No second key is false. Changing the MFA Boolean to true in order to see `READY` would be a different file. The published checklist does not make that change. | Stored by the false Boolean | Not stored | |---|---| | The key is unmet | Which of three accounts | | It is the only unmet key | A name, a factor type, a serial | | The line names that key | The word READY | ### 15.2 Worked example | Reading | What `missing` holds | Decision | |---|---|---| | NOT READY names one key | `admin accounts use MFA` | Keep | | READY is the empty-list branch | The list has one key | Keep as the other branch | | "The script reports 2 of 3 accounts." | No account count is stored | Refuse | | "Two unmet keys were joined." | One Boolean is false | Refuse | > **Synthetic case.** The volunteer administrator remains unnamed. ### Errors and limits Do not turn one Boolean into a census of the three accounts. ### Apply - **EX061 — The false key.** The last line says `NOT READY: admin accounts use MFA`. A classmate rewrites it as `2 of 3` and adds the unfinished volunteer's name. What does the line actually contain? *Rubric:* 3 = one false key, named in full, after `NOT READY:`; `READY` is not printed; three accounts and one unfinished volunteer stay prose; no name and no `2 of 3` are in the script;; 2 = the printed line stays and the census stays out;; 1 = one token;; 0 = none. ### Continue studying — lesson 15 (chapter 15 of 20) [← Chapter 14](#ch-14) · [Course chapter index](../SUBJECTS.md) · [Chapter 16 →](#ch-16) Continue to the next authored lesson. ## Worked answers **EX061.** The line is `NOT READY: admin accounts use MFA`. One key is false. Three accounts and one unfinished volunteer are prose. No name and no fraction are stored.