A Backbone Model without constructor

CarBackboneModel.js

//Create a Car Model
var Car = Backbone.Model.extend({

	//Validate the Car Model
	validate: function(attr) {
		if( !(attr.brand && attr.model && attr.color) ) {
			return "Error Occurred";
		}
	},

	//Initialize is called after the Model object is constructed
	initialize: function() {

		//if there's an validation error invoke this function
		this.bind("error", function (model, error) { 
			console.log(error);
		});

		console.log('Inside initialize');
	}

});

//Create an instance of Car
var carObj = new Car({brand: 'Ford', model: 'Figo'});

//carObj is created successfully
console.log(carObj);	

//check if it is valid
console.log('Is Model valid: ' + carObj.isValid());

//This will throw an error
carObj.set({name: 'Honda'});