That's a map...

src/markets/gingering.js

@@ -15,7 +15,7 @@ App.Entity.GingeringParameters = class {
 		// figure out what type of gingering applies, if any
 		if (applyLawCheck(market) === 1 && V.policies.SMR.honestySMR === 1) {
 			/* SMR prohibits gingering and is enforced for this seller - do nothing */
-		} else if (App.Data.misc.schools.keys().includes(market)) {
+		} else if (App.Data.misc.schools.has(market)) {
 			/* slave schools have a reputation to maintain, and will never ginger their slaves */
 		} else if (["wetware", "heap", "gangs and smugglers", "low tier criminals", "military prison", "white collar", "corporate"].includes(market)) {
 			/* these sellers see no reason to ginger their slaves */