function setNullSettlementChallengeState(NullSettlementChallengeState newNullSettlementChallengeState)
    public
    onlyDeployer
    notNullAddress(address(newNullSettlementChallengeState))
    {
        NullSettlementChallengeState oldNullSettlementChallengeState = nullSettlementChallengeState;
        nullSettlementChallengeState = newNullSettlementChallengeState;
        emit SetNullSettlementChallengeStateEvent(oldNullSettlementChallengeState, nullSettlementChallengeState);
    }