code: function() {
  		var hashKey = _.result( this, 'hashAttribute' ) || _.result( this, 'idAttribute' ),
  			rangeKey = _.result( this, 'rangeAttribute' ),
  			hashValue = this.get( hashKey ),
  			rangeValue = rangeKey ? this.get( rangeKey ) : null;
  
  		return hashValue == null || ( rangeKey && rangeValue == null );
  	}
docs: Determines if the model is new.