Creating a shopping cart application with InheritedModel

This will be very similar to InheritedWidget, with slight changes in how we extract the latest values of the variables. Create a new app named cart_inherited_model and copy everything from the previous section. Then, proceed as follows:

1. Let's update our boilerplate code first. Rename the inherited_widget_cart.dart file inherited_model_cart.dart, remove all the contents, and add the following code:

   import 'package:flutter/material.dart';
   import 'item.dart';
   class MyCartInheritedModelWidget extends StatefulWidget {
     final Widget child;
     const MyCartInheritedModelWidget({Key? key, required 
     this.child}) : super(key: key);
     static MyCartInheritedModelWidgetState 
     of(BuildContext context) {
       final MyCartInheritedModelWidgetState? result =
           context.dependOnInheritedWidgetOfExactType...