code: function runTx (raw, cb) {
    // create a new transaction out of the json
    var tx = new Transaction(raw)
  
    // tx.from
    tx.sign(Buffer.from(keyPair.secretKey, 'hex'))
  
    console.log('----running tx-------')
    // run the tx \o/
    vm.runTx({
      tx: tx
    }, function (err, results) {
      createdAddress = results.createdAddress
      // log some results
      console.log('gas used: ' + results.gasUsed.toString())
      console.log('returned: ' + results.vm.return.toString('hex'))
      if (createdAddress) {
        console.log('address created: ' +
            createdAddress.toString('hex'))
      }
  
      cb(err)
    })
  }
docs: runs a transaction through the vm