old_contents: /*
   * Example - Running code on an ethereum-vm
   *
   *
   * To run this example in the browser, bundle this file
   * with browserify using `browserify index.js -o bundle.js`
   * and then load this folder onto a HTTP WebServer (e.g.
   * using node-static or `python -mSimpleHTTPServer`).
   */
  const BN = require('bn.js')
  const VM = require('../../dist').default
  
  // Create a new VM instance
  // For explicity setting the HF use e.g. `new VM({ hardfork: 'petersburg' })`
  const vm = new VM()
  
  const STOP = '00'
  const ADD = '01'
  const PUSH1 = '60'
  
  // Note that numbers added are hex values, so '20' would be '32' as decimal e.g.
  const code = [PUSH1, '03', PUSH1, '05', ADD, STOP]
  
  vm.on('step', function (data) {
    console.log(`Opcode: ${data.opcode.name}\tStack: ${data.stack}`)
  })
  
  vm.runCode({
    code: Buffer.from(code.join(''), 'hex'),
    gasLimit: new BN(0xffff),
  })
    .then((results) => {
      console.log('Returned : ' + results.returnValue.toString('hex'))
      console.log('gasUsed  : ' + results.gasUsed.toString())
    })
    .catch(console.error)
  
new_contents: /*
   * Example - Running code on an ethereum-vm
   *
   *
   * To run this example in the browser, bundle this file
   * with browserify using `browserify index.js -o bundle.js`
   * and then load this folder onto a HTTP WebServer (e.g.
   * using node-static or `python -mSimpleHTTPServer`).
   */
  const BN = require('bn.js')
  const VM = require('../../dist').default
  
  // Create a new VM instance
  // To explicity set the chain or hardfork use [Common](https://github.com/ethereumjs/ethereumjs-vm/tree/master/packages/common#usage)
  const vm = new VM()
  
  const STOP = '00'
  const ADD = '01'
  const PUSH1 = '60'
  
  // Note that numbers added are hex values, so '20' would be '32' as decimal e.g.
  const code = [PUSH1, '03', PUSH1, '05', ADD, STOP]
  
  vm.on('step', function (data) {
    console.log(`Opcode: ${data.opcode.name}\tStack: ${data.stack}`)
  })
  
  vm.runCode({
    code: Buffer.from(code.join(''), 'hex'),
    gasLimit: new BN(0xffff),
  })
    .then((results) => {
      console.log('Returned : ' + results.returnValue.toString('hex'))
      console.log('gasUsed  : ' + results.gasUsed.toString())
    })
    .catch(console.error)
  
subject: update hf example