合约地址:https://mumbai.polygonscan.com/address/0xab741a75f7b52b5475733ebd5e61a1be781613e6
Mint: https://mumbai.polygonscan.com/tx/0xf0f68403ace28e364d35c82c0ebd1a3437fc43efc89eaa3a40f73843433722dd
truffle micrate --network development
truffle micrate --network mumbai
truffle test ./test/Lesson4ERC20.test.js