Can't Extend Hash?

[Brandon]

Hi everyone,

I wanted to extend Hash so I can write a caching mechanism, but I got
an error when I tried to create an instance of my class:

        arguments.callee.caller.__parent is undefined


My code is the following:

        var Cache = new Class({

            Extends : Hash,

            initialize : function() {
                this.parent();
            }

        });

        var cacheInstance = new Cache();


What am I doing wrong?

Thanks,
Brandon