ericwindmill

import 'dart:collection';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

class Person {
  Person({this.name, this.initialAge});

  final String name;
  final int initialAge;

ericwindmill

import 'dart:collection';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

class Person with ChangeNotifier {
  Person({this.name, this.age});

  final String name;
  int age;

ericwindmill

import 'dart:async';
import 'dart:collection';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

class Product {
  final String name;
  final double cost;

  Product({this.name, this.cost});