How to use the busyman.isNil function in busyman

function registerDevice(freebird, dev, callback) {
    var devId, oldDev;

    if (!validate.isDevice(dev)) {
        setImmediate(callback, new TypeError('Input dev is not a valid device instance'));
        return freebird;
    }

    devId = dev.get('id');
    oldDev = _.isNil(devId) ? undefined : freebird.findById('device', devId);

    if (oldDev) {
        setImmediate(callback, new Error('Device with id: ' + devId + ' already exists, unregister it first'));
        return freebird;
    }

    if (dev._recovering) {   // recovered from database (when at booting up or restarting stage)
        freebird._devbox.set(devId, dev, function (err, id) {
            if (!err)
                dev._recovering = false;

            callback(err, id);
        });
    } else {
        dev._poke();
        dev.set('net', {

rRpt.max = setInterval(() => {
      rAttrs.mute = true
      dumper((err, val) => {
        if (err) console.warn(err)
        rAttrs.mute = false
        notifier.data = val
        qn.notify(notifier, () => {})
      })

      if (!_.isNil(rRpt.min)) clearTimeout(rRpt.min)

      rRpt.min = null
      rRpt.min = setTimeout(() => {
        if (pmin === 0) {
          rAttrs.mute = false
        } else {
          dumper((err, val) => {
            if (err) console.warn(err)
            rAttrs.mute = false
            notifier.data = val
            qn.notify(notifier, () => {})
          })
        }
      }, pmin)
    }, pmax)

function invokeCb (qn, msg, status, data, cb) {
  if (_.isFunction(cb)) {
    process.nextTick(() => {
      cb(status, data)
    })
  }

  if (!_.isNil(data)) reporter.checkAndReportResource(qn, msg.oid, msg.iid, msg.rid, data)
}

function buildAttrsAndRsc(cn, ssid, oid, iid, rid) {
    var attrs = cn._getAttrs(ssid, oid, iid, rid),
        allowedAttrs = [ 'pmin', 'pmax', 'gt', 'lt', 'stp' ],
        target = cn._target(oid, iid, rid),
        value,
        data;

    if (!_.isNil(iid)) 
        value = cn.getSmartObject().dumpSync(oid, iid);
    else 
        value = cn.getSmartObject().dumpSync(oid);

    data = cutils.encodeLinkFormat(target.pathKey, value, attrs);

    return data;
}

delete this._maxListeners

  Object.defineProperty(this, 'domain', _.assign({ value: _domain }, propWritable))
  Object.defineProperty(this, '_events', _.assign({ value: __events }, propWritable))
  Object.defineProperty(this, '_eventsCount', _.assign({ value: __eventsCount }, propWritable))
  Object.defineProperty(this, '_maxListeners', _.assign({ value: __maxListeners }, propWritable))
  /** ***************************************************************************************** */

  if (arguments.length === 1 && _.isObject(name)) {
    settings = name
    name = null
  }

  settings = settings || {}

  if (!_.isNil(name) && !_.isString(name)) throw new TypeError('name should be a string if gieven.')
  else if (!_.isPlainObject(settings)) throw new TypeError('settings should be an object if gieven.')

  /** ************************************************ */
  /** * Prepare Shepherd Settings                   ** */
  /** ************************************************ */
  this.name = name || config.shepherdName

  Object.defineProperty(this, 'clientId', _.assign({ value: this.name }, propWritable))
  Object.defineProperty(this, 'brokerSettings', _.assign({ value: settings.broker || config.brokerSettings }, propWritable))
  Object.defineProperty(this, 'defaultAccount', _.assign({ value: settings.account || config.defaultAccount }, propWritable))

  this.clientConnOptions = settings.clientConnOptions || config.clientConnOptions
  this.reqTimeout = settings.reqTimeout || config.reqTimeout
  this.devIncomingAcceptanceTimeout = settings.devIncomingAcceptanceTimeout || config.devIncomingAcceptanceTimeout
  /** ************************************************ */
  /** * Protected Memebers                          ** */