function withdraw()
        public
    {
        require(donationData[msg.sender] > 0);
        require(block.timestamp > (timeStarted + expirationInSeconds));
        require(hasBeenClaimed == false);

        var value = donationData[msg.sender];
        donationData[msg.sender] = 0;
        msg.sender.transfer(value);
        
        
    }