Hello fellows, how you doing?

I build my custom template for invoice analysis and it's being displayed twice. The first one empty once any search was did and the second when it returns a search result... May could some one help me?

start: function() {
        var sup = this._super();
        var self = this;
        self.render();
    },
    /*render template passing no values*/
    render: function(){
        var self = this;
        var invoices = Invoices.call('dashboard_invoceis_action_id', []).then(function(result){
            self.$el.append(QWeb.render('InvoiceTemplate', {invoices: result}));
        });
    },
    do_search: function(event) {
        var self = this;
        if(event.which == 13) {
            var search_term = $(event.currentTarget).val();
            var invoice_id = $(event.currentTarget).data('export-id');
            var invoices = Invoices.call('do_search', [{'search_term':search_term}]).then(function(result){
                self.$el.append(QWeb.render('InvoiceTemplate', {invoices: result}));
            });
        }
    },