function to
        
        Auction storage auction = tokenIdToAuction[_tokenId];

        
        
        require(auction.live);
        require(auction.endTime > block.timestamp);

        
        
        require(msg.value > auction.highestBid);

        if (auction.highestBidder != 0) {
            
            
            
            
            
            pendingReturns[auction.highestBidder] += auction.highestBid;
        }