Handlebars SWAG library

I'm new in Handlebars and I'm trying to use SWAG library for custom helpers but unsuccess. For example I try to display in my file.handlebars {{lowercase "BENDER SHOULD NOT BE ALLOWED ON TV"}} and I get the error Error: Could not find property 'lowercase' I ran npm install swag

my app.js is:

var express = require('express')
  , http = require('http')
  , routes = require('./routes')
  , path = require('path')
  ,Swag = require('swag')
  , handlebars = require('handlebars');

var app = express();
var engines = require('consolidate');
app.engine('handlebars', engines.handlebars);

app.configure(function() {
    app.set('view engine', 'handlebars');
    app.set('views', __dirname + '/views');
    app.set('port', process.env.PORT || 3000);
    app.use(express.favicon());
    app.use(express.logger('dev'));
    app.use(express.bodyParser());
    app.use(express.methodOverride());
    app.use(app.router);
    app.use(express.static(path.join(__dirname, 'public')));
});

app.get('/dashBoard', routes.getDashboard);

http.createServer(app).listen(app.get('port'), function(){
  console.log('Express server listening on port ' + app.get('port'));
});

Thank in advance for your help

Alcudia