Hi.

I want to inherit function "get_due" of "Models.Order".

Here is the code in original function in a file point_of_sale/static/src/js/models.js:

get_due: function(paymentline) {
    if (!paymentline) {
        var due = this.get_total_with_tax() - this.get_total_paid();
    } else {
        var due = this.get_total_with_tax();
        var lines = this.paymentlines.models;
        for (var i = 0; i < lines.length; i++) {
            if (lines[i] === paymentline) {
                break;
            } else {
                due -= lines[i].get_amount();
            }
        }
    }
    return round_pr(due, this.pos.currency.rounding);
},

i want to customize that function and add some code like this: 

odoo.define('pos_mi_module.mi_module', function (require) {
    "use strict";

    var Models = require('point_of_sale.models');

    Models.Order = Models.Order.extend({
        get_due: function (paymentline) {
            if (!paymentline) {
                var due = this.get_total_with_tax() - this.get_total_paid();
            } else {
                var due = this.get_total_with_tax();
                var lines = this.paymentlines.models;
                for (var i = 0; i < lines.length; i++) {
                    if (lines[i] === paymentline) {
                        break;
                    } else {
                        due -= lines[i].get_amount();
                    }
                }
            }
            return round_pr(due, this.pos.currency.rounding);
        },
    });
})

and after updating the module when i enter the session of the POS it remains black, without showing anything, and no error appears in the browser console. Both codes of "get_due" are the same because use copy and paste. What happen with this?.

Thanks in advance