## 要件 - MultiToken standardの理解を深めること ## 参考文献 - https://docs.openzeppelin.com/contracts/3.x/erc1155 - https://docs.openzeppelin.com/contracts/3.x/erc777 - https://docs.openzeppelin.com/contracts/3.x/erc721 - https://docs.openzeppelin.com/contracts/3.x/erc20
