{"id":"root-nonnull-precondition","text":"`averageOfLevels` assumes root is non-null; passing `None` raises `AttributeError` with no graceful handling.","truth_value":"IN","source":"entries/2026/06/06/average-of-levels-in-binary-tree-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"root-nonnull-precondition","truth_value":"IN","reason":"premise"}]}}