How to use the is2.bool function in is2

var deferred = getDeferred();
    var timeoutId;
    var timedout = false;
    var retryId;

    // the first arument may be an object, if it is not, make an object
    var opts;
    if (is.obj(port)) {
        opts = port;
    } else {
        opts = makeOptionsObj(port, host, inUse, retryTimeMs, timeOutMs);
    }

    //debug('opts:'+util.inspect(opts);

    if (!is.bool(opts.inUse)) {
        deferred.reject(new Error('inUse must be a boolean'));
        return deferred.promise;
    }

    if (!is.positiveInt(opts.retryTimeMs)) {
        opts.retryTimeMs = RETRYTIME;
        debug('set retryTime to default '+RETRYTIME+'ms');
    }

    if (!is.positiveInt(opts.timeOutMs)) {
        opts.timeOutMs = TIMEOUT;
        debug('set timeOutMs to default '+TIMEOUT+'ms');
    }

    function cleanUp() {
        if (timeoutId) {