Ember inject function

I have some function which i use in couple controllers

 App.AController=Ember.Controller.Extend({
    area:function(){}
});
App.BController=Ember.Controller.Extend({
    area:function(){}
});

cause i new in Ember i want something to write function in one place and then inject function in Controllers. I try something with services but doesn't work i got error that Ember.Service is not defined, so if someone can write example! I use ember 1.10.