如何获取账户near_sdk_sim的近余额？

const near = require('near-api-js');

async function getAccountBalance() {
  const nearConfig = {
    networkId: 'testnet', // 网络ID，可以是testnet或mainnet
    nodeUrl: 'https://rpc.testnet.near.org', // NEAR节点的URL
    walletUrl: 'https://wallet.testnet.near.org', // NEAR钱包的URL
    helperUrl: 'https://helper.testnet.near.org', // NEAR助手的URL
    explorerUrl: 'https://explorer.testnet.near.org', // NEAR区块浏览器的URL
  };

  const keyStore = new near.keyStores.InMemoryKeyStore();
  const nearProvider = new near.providers.JsonRpcProvider(nearConfig.nodeUrl);
  const nearAccount = new near.Account(nearProvider);

  const accountId = 'near_sdk_sim'; // 要查询余额的账户ID

  const accountBalance = await nearAccount.getAccountBalance(accountId);
  console.log(`账户 ${accountId} 的近余额为: ${accountBalance.total}`);
}

getAccountBalance();