function startUnitRaffle(uint256 endTime, uint256 unitId) external {
        require(msg.sender == owner);
        require(block.timestamp < endTime);
        
        if (unitRaffleRareId != 0) { 
            require(unitRaffleWinner != 0);
        }
        
        
        unitRaffleWinningTicketSelected = false;
        unitRaffleTicketThatWon = 0;
        unitRaffleWinner = 0;
        unitRaffleTicketsBought = 0;
        
        
        unitRaffleEndTime = endTime;
        unitRaffleRareId = unitId;
        unitRaffleId++; 
    }