function determineReward(uint _challengeID) public view returns (uint) {
        require(!challenges[_challengeID].resolved && voting.pollEnded(_challengeID));

        
        if (voting.getTotalNumberOfTokensForWinningOption(_challengeID) == 0) {
            return 2 * challenges[_challengeID].stake;
        }

        return (2 * challenges[_challengeID].stake) - challenges[_challengeID].rewardPool;
    }