## Chapter 5 — The lease print is not the router checklist ### Lesson map Lesson 05. Map, example, EX051. ```mermaid flowchart TD A["lab_leases.py compares two sets"] --> B["Seven rows, two UNKNOWN"] C["lab_router.py evaluates seven flags"] --> D["Print: 2 of 7 pass"] B --> E{"May one print answer the other question?"} D --> E E -->|No| F["Quote the script that measured it"] ``` The lease run is a set comparison. The router run is a list of flags. ### Logical drawing ```text lease print seven rows unknown: ['bb:77', 'cc:19'] known but not seen: [] router print PASS Wi-Fi uses WPA2 or WPA3 PASS guest network enabled five FIX lines 2 of 7 pass ``` ### Learning outcomes After this chapter, you should be able to: 1. Name the question each script answers. 2. Keep both prints. 3. Refuse a note that treats one score as the other measurement. ### 5.1 Two instruments, taken on two different objects. A measurement is only as good as the question it was built to answer. `lab_leases.py` holds a dictionary of five known hardware labels and a list of seven leases. It prints each lease, looks the label up, and then prints the set difference in both directions. The embedded run therefore ends with `unknown: ['bb:77', 'cc:19']` and `known but not seen: []`. That is an inventory comparison. It does not read a password flag, a firmware age, or an isolation boolean. `lab_router.py` holds a different object: a dictionary of settings. It evaluates seven predicates and prints `PASS` or `FIX` for each, then `2 of 7 pass`. The two passing predicates are the Wi-Fi mode check and the guest-network check. The script never opens the lease list. A classmate who writes the unknown-device count into the router score, or who deletes the five `FIX` lines because the lease comparison "looked tidy," is reporting a quantity the second script did not compute. Chapter 3 also separates practice from operations. The lease block is labelled synthetic, and the prose says Leo practises the comparison before a live export. The live export's rows are not in this file. The router block is likewise a synthetic settings dictionary. Chapter 4 later tells a story in which the checklist is considered again after changes. That story is not a second copy of `lab_router.py`. Leave both embedded runs as the only machine output the book contains. ### 5.2 Worked example Match the sentence to the instrument that can support it. | Cited line | Instrument | Decision | |---|---|---| | `unknown: ['bb:77', 'cc:19']` | Lease comparison | Keep it on that print | | `known but not seen: []` | Lease comparison | Keep the empty side | | `2 of 7 pass` | Router flags | Keep it on that print | | "So the leases now pass 2 of 7." | Neither script | Refuse | > **Synthetic case.** Both prints belong to the Bramble Street exercise. Neither is a re-run of the other. ### Errors and limits A tidy inventory can sit beside a weak configuration. The two files are not drafts of one score. ### Apply - **EX051 — Which instrument?** The lease run lists seven rows and names two unknown labels. The router run says 2 of 7 pass. May the router score replace the lease print? *Rubric:* 3 = no; both prints stay; the lease lines stay seven rows, unknown bb:77 and cc:19, and known-but-not-seen empty; the router print stays 2 of 7 with Wi-Fi and the guest network as the passes; do not edit either script;; 2 = the two prints stay different;; 1 = one print;; 0 = none. ### Continue studying — lesson 05 (chapter 05 of 20) [← Chapter 04](#ch-04) · [Course chapter index](../SUBJECTS.md) · [Chapter 06 →](#ch-06) Continue to the next authored lesson. ## Worked answers **EX051.** No. Both prints stay. The lease lines stay seven rows, with unknown bb:77 and cc:19 and an empty known-but-not-seen side. The router print stays 2 of 7, and the two passes stay the Wi-Fi mode and the guest network. Do not edit either script.