Quick note about objects as YUI3 attributes default values

gistfile1.js

/**
 * If you want to set the default value of an attribute to be an array or object,
 * doing this fails:
 */
var MyClass = Y.Base.create('myClass', Y.Base, [], {}, {
	ATTRS: {
		myAttr: { value: [] }
	}
});

/**
 * ... because you're assigning _one_ array to all the instances of MyClass.
 * To avoid this problem, valueFn comes to the rescue:
 */
var MyClass = Y.Base.create('myClass', Y.Base, [], {}, {
	ATTRS: {
		myAttr: { valueFn: Array }
	}
});

It appears that Y.Array() returns not an empty array but an array with an undefined first item. This is probably a bug.