{"id":"reduce-empty-guard-required","text":"`reduce(or_, nums)` with no initializer raises `TypeError` on an empty list; the early-return guard in `subsetXORSum` is load-bearing, not defensive.","truth_value":"IN","source":"entries/2026/06/06/sum-of-all-subset-xor-totals-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"reduce-empty-guard-required","truth_value":"IN","reason":"premise"}]}}