I am trying to hide a particular stage using the stage name in sales pipeline of odoo 8,

i.e,

var kanbanview = instance.web_kanban;

kanbanview.KanbanView.include({

     do_process_groups: function (groups) {

        var self = this;

         this._super(groups);

         for (var key in self.groups) {

              if (self.groups[key]['title'] == 'Waiting for approval'){

                     var test = self.groups[key].$el;

                     test.css("display", "None");

            }

} },

});

   I have used this method in odoo 9 and it is working. But in odoo 8, 'self.groups' is an object which has all the stages in it, but I am unable to  iterate through the stages in it. Is there any other way to do it ?
('Waiting for approval' is  the name of the stage which I have created) 
Thank you