How to use the @tradle/constants.SIG function in @tradle/constants

var rufusPriv = require('./fixtures/rufus-priv')
var rufus = Identity.fromJSON(rufusPub)
var constants = require('@tradle/constants')
// var testDrivers = require('./helpers/testDriver')
var BASE_PORT = 33333
var billPort = BASE_PORT++
var tedPort = BASE_PORT++
var rufusPort = BASE_PORT++
var bootstrapDHT
var BOOTSTRAP_DHT_PORT = BASE_PORT++
var TYPE = constants.TYPE
var ROOT_HASH = constants.ROOT_HASH
var CUR_HASH = constants.CUR_HASH
var PREV_HASH = constants.PREV_HASH
var NONCE = constants.NONCE
var SIG = constants.SIG
var STORAGE_DIR = path.resolve('./storage')
// var tedHash = tedPub[ROOT_HASH] = 'c67905793f6cc0f0ab8d20aecfec441932ffb13d'
// var billHash = billPub[ROOT_HASH] ='fb07729c0cef307ab7c28cb76088cc60dbc98cdd'
// var tedHash = 'c67905793f6cc0f0ab8d20aecfec441932ffb13d'
// var billHash = 'fb07729c0cef307ab7c28cb76088cc60dbc98cdd'
var help = require('@tradle/test-helpers')
// var fakeKeeper = help.fakeKeeper
var fakeWallet = help.fakeWallet
var FakeKeeper = help.fakeKeeper
// var bill = Identity.fromJSON(billPriv)
// var ted = Identity.fromJSON(tedPriv)
var NETWORK_NAME = 'testnet'
// var blockchain = new Fakechain({ networkName: NETWORK_NAME })
var Driver = require('../')
Driver.CATCH_UP_INTERVAL = 1000
// Driver.SEND_THROTTLE = 1000

function checkMessage (m) {
      if (Buffer.isBuffer(m)) m = JSON.parse(m)

      delete m[constants.SIG]
      t.deepEqual(m, msg)
    }