function upgradeUnitMultipliers(address player, uint256 upgradeClass, uint256 unitId, uint256 upgradeValue) internal {
        uint256 productionGain;
        if (upgradeClass == 0) {
            unitGooProductionIncreases[player][unitId] += upgradeValue;
            productionGain = unitsOwned[player][unitId] * upgradeValue * (10 + unitGooProductionMultiplier[player][unitId]);
            increasePlayersGooProduction(player, productionGain);
        } else if (upgradeClass == 1) {
            unitGooProductionMultiplier[player][unitId] += upgradeValue;
            productionGain = unitsOwned[player][unitId] * upgradeValue * (schema.unitGooProduction(unitId) + unitGooProductionIncreases[player][unitId]);
            increasePlayersGooProduction(player, productionGain);
        } else if (upgradeClass == 2) {
            unitAttackIncreases[player][unitId] += upgradeValue;
        } else if (upgradeClass == 3) {
            unitAttackMultiplier[player][unitId] += upgradeValue;
        } else if (upgradeClass == 4) {
            unitDefenseIncreases[player][unitId] += upgradeValue;
        } else if (upgradeClass == 5) {
            unitDefenseMultiplier[player][unitId] += upgradeValue;
        } else if (upgradeClass == 6) {
            unitGooStealingIncreases[player][unitId] += upgradeValue;
        } else if (upgradeClass == 7) {
            unitGooStealingMultiplier[player][unitId] += upgradeValue;
        } else if (upgradeClass == 8) {
            unitMaxCap[player][unitId] = upgradeValue; 
        }
    }