Ember.js how to call super class or base class method from subclass?

When ever i try to call a base class method from subclass in ember.js I get the following error

Assertion failed: Ember.Object.create no longer supports defining methods that call _super

App.BaseClass = Ember.Object.extend({
 sayHello: function(){
   //my code
}
});

App.SubClass = App.BaseClass.extend({
//some code here 

sayHellow: function(){
//some code of subclass
.
.
.
this_super(); // This causes error: Assertion failed: Ember.Object.create no //longer supports defining methods that call _super
}
});