function _giveRuling(uint _disputeID, uint _ruling) internal {
        DisputeStruct storage dispute = disputes[_disputeID];
        require(_ruling <= dispute.choices, "Invalid ruling.");
        require(dispute.status != DisputeStatus.Solved, "The dispute must not be solved already.");

        dispute.ruling = _ruling;
        dispute.status = DisputeStatus.Solved;

        msg.sender.send(dispute.fee); 
        dispute.arbitrated.rule(_disputeID,_ruling);
    }