## Chapter 14 — Four ticks are not a printed fraction ### Lesson map Lesson 14. Map, example, EX060. ```mermaid flowchart TD D["Five Booleans in insertion order"] --> M["x when true, space when false"] M --> S["Sum of the true values is 4"] S --> Q{"Does the script print 4 of 5?"} Q -->|No| K["Leave 4 of 5 as a label beside the lines"] ``` The fraction is arithmetic. The page shows brackets. ### Logical drawing ```text [x] official source used [x] hash matches vendor [x] backup taken [x] tested on staging copy [ ] admin accounts use MFA true values: 4 keys: 5 printed fraction: none ``` ### Learning outcomes After this chapter, you should be able to: 1. Count the true values without replacing the print. 2. Explain the bracket as a one-character flag. 3. Keep dictionary order distinct from importance. ### 14.1 Insertion order prints five lines. The sum is not one of them. `checks` is a dictionary of five strings to Booleans. Python 3.7 and later preserve insertion order. This file does not sort the keys. The loop prints `[x]` when the Boolean is true and `[ ]` when it is false, then the key. Four values are `True`. One is `False`. Someone may write "four true, five keys" in the margin. The loop's own page never contains that fraction, a slash form, or a percentage. The false key is last because it was written last, not because multi-factor sign-in was judged the least important. Moving that key to the top of the dictionary would move its blank bracket. The published file does not move it. A quality, a duration, or a witness cannot be stored in a Boolean. The `x` does not say how the hash was obtained, and the blank does not name a person. Decan et al. (2018) study vulnerabilities across a package network. Their counts are not these five Booleans. SSDF (NIST SP 800-218) groups secure-development practices. This dictionary is not a scored SSDF assessment. OWASP ASVS is likewise not scored. The five lines remain five lines. | Key, in written order | Boolean | Bracket | |---|---|---| | official source used | True | x | | hash matches vendor | True | x | | backup taken | True | x | | tested on staging copy | True | x | | admin accounts use MFA | False | space | ### 14.2 Worked example | Offered summary | Relation to the print | Decision | |---|---|---| | Four `x` brackets and one blank | The five Booleans | Keep | | "4 of 5" written beside the lines and marked as a count | Not a line the script prints | May stay if labelled | | "The script's last line is `4 of 5`." | The last line is the blank MFA bracket | Refuse | | "The blank is last because it matters least." | It is last because of insertion order | Refuse | > **Synthetic case.** The five keys are the whole checklist. ### Errors and limits Label derived counts as counts. Do not slide them into the output. ### Apply - **EX060 — Beside, not instead.** Someone replaces the five bracket lines with the single sentence `4 of 5` and says the blank is last because it is the least important check. What may a count do, and why is the blank last? *Rubric:* 3 = 4 true values out of 5 keys may be labelled beside the print; the script does not print that fraction; the blank is last by insertion order; the five lines stay;; 2 = the brackets stay and the fraction is not the output;; 1 = one line;; 0 = none. ### Continue studying — lesson 14 (chapter 14 of 20) [← Chapter 13](#ch-13) · [Course chapter index](../SUBJECTS.md) · [Chapter 15 →](#ch-15) Continue to the next authored lesson. ## Worked answers **EX060.** Four true values and five keys may be labelled beside the brackets. The script does not print `4 of 5`. The blank bracket is last because that key was written last.