问NFT市场需要他们自己的稳固契约吗？

EN

contract NFTMarket is ReentrancyGuard {
  ...
  function createMarketItem(
    address nftContract,
    uint256 tokenId,
    uint256 price
  ) public payable nonReentrant {
    require(price > 0, "Price must be at least 1 wei");
    require(msg.value == listingPrice, "Price must be equal to listing price");

    _itemIds.increment();
    uint256 itemId = _itemIds.current(); 

    idToMarketItem[itemId] =  MarketItem(
      itemId,
      nftContract,
      tokenId,
      payable(msg.sender),
      payable(address(0)),
      price,
      false
    );
...