如何在dartFlutter中按日期对列表进行排序排序

我有下面的列表，我正试图按日期时间重新排序.

import 'package:intl/intl.dart'; 
//don't forget to add under dependencies pubspec.yml "intl: ^0.15.8"


List products = [];

//adding into the new list from raw API list
for(final item in rawProducts){

   var parsedDate = DateTime.parse.(item['expiryDate']);
   tmpArray = {
     'id': item['id'],
     'name': item['name'],
     'price': item['price'],
     'expiry': parsedDate
   }
   products.add(tmpArray);
  }
}


List products = [

 {id: 1242, name: milk, price: $5, expiry: 2019-11-25 00:00:00:000},
 {id: 1242, name: egg, price: $2, expiry: 2019-11-22 00:00:00:000},
 {id: 1243, name: bread, price: $3, expiry: 2019-11-22 00:00:00:000},
 {id: 1244, name: butter, price: $7, expiry: 2019-11-24 00:00:00:000},
 {id: 1247, name: butter, price: $7, expiry: 2019-11-23 00:00:00:000},

]

我想以最远到期日期最先显示的方式重新排列列表:

 25-11-2019
 24-11-2019
 23-11-2019
 22-11-2019
 22-11-2019

What I have tried (updated) -> SOLVED by changing a.expiry into a['expiry'] :

  products.sort((a,b) {
    var adate = a['expiry'] //before -> var adate = a.expiry;
     var bdate = b['expiry'] //var bdate = b.expiry;
     return -adate.compareTo(bdate);
  });

在排序函数上，我收到此错误(通过上面的修复解决):

Unhandled Exception: NoSuchMethodError: Class 
'_InternalLinkedHashMap<String, dynamic>'has no instance getter 'expiry'.