import { Session } from '@0xsequence/auth'
import { ethers } from 'ethers'
 
const config = {
  mnemonic: 'YOUR MNEMONIC',
  projectAccessKey: 'YOUR PROJECT ACCESS KEY',
  chainId: ChainId.YOUR_CHAIN_ID // e.g. ChainId.MAINNET, ChainId.POLYGON, etc.
}
 
const signer = ethers.Wallet.fromMnemonic(config.mnemonic)
 
const session = await Session.singleSigner({ signer, projectAccessKey: config.projectAccessKey })
 
const account = session.account.getSigner(config.chainId, {
  async selectFee(_transactions, options) {
    // This callback is called with the list of candidate fee options.
 
    console.log('Fee options:', JSON.stringify(options, undefined, 2))
 
    // Select the USDC fee option.
    return options.find(option => option.token.symbol === 'USDC')
  }
})