function mintReward(
        address _lucker,
        uint256 _slotId,
        uint256 _value,
        RewardType _rewardType)
        private
    {
        
        rewardBalance[_lucker] = rewardBalance[_lucker].add(_value);
        
        rewardContract.mintReward(
            _lucker,
            curRoundId,
            slot[_slotId].tNumberFrom,
            slot[_slotId].tNumberTo,
            _value,
            uint256(_rewardType)
        );
    }