private async Task CheckAuthorizationToDeliver()
        {
            Delivery_man d1 = (Delivery_man)await myHttpClient.sendHttpGetAsyncObject <Delivery_man>(Constants.ApiGetDeliveryManById + "?id_delivery_man=" + App.deliveryMan.id_delivery_man);

            if (!d1.authorized)
            {
                MyHelper.RemoveAllSavedValuesForApp();

                NavigationPage np = new NavigationPage(new SignInPage());
                MainPage = np;
            }
        }