const Account = require('@mutadev/account');

const account = new Account('0x...');
account.signTransaction({
  service: '...',
  method: '...',
  payload: '{...}',
  sender: '0x...',
});

const Account = require('@mutadev/account');

const account = new Account('0x...');
// a signed transaction from another account
const signedTransaction = {};

account.signTransaction(signedTransaction);