function NotAnArray(o) {

	if (o.constructor === Array) {
		this.data = null;
	} else {
		this.data = o;
	}

}

NotAnArray.prototype.toString = function () {
	return 'I\'m not an array!';
};

NotAnArray.prototype.whatAmI = function () {
	return 'Totally not an array.';
};

testValue = new NotAnArray('blah');