List<Boolean> newParametersNullability = parametersNullabilityOf(newBehavior)

            for (int idx = 0; idx < oldParametersNullability.size(); idx++) {
                def oldNullability = oldParametersNullability[idx]
                def newNullability = newParametersNullability[idx]
                if (oldNullability && !newNullability) {

        } finally {
            THREAD_POOL.shutdown()
        }
    }

    static void checkCommit(String commit) {
        List<String> parentCommits = parentCommitsOf(commit)
        if (parentCommits.size() != 2) {
            println("$commit is not a merge commit we're looking for. Parents: $parentCommits")
            return
        }

        // The correct state we are looking for is:
        // 1. It's a merge commit.