Class '_InternalLinkedHashMap<String, dynamic>' has no instance getter 'timestamp'. Receiver: _LinkedHashMap len:7 Tried calling: timestamp Flutter

if i delete the following code works fine but i need it for my other screen, this is the error and code:

Class '_InternalLinkedHashMap<String, dynamic>' has no instance getter 'timestamp'. Receiver: _LinkedHashMap len:7 Tried calling: timestamp

@override
  Widget build(BuildContext context) {
    appController.mydate=DateTime.parse(info.timestamp).toLocal().toString().substring(0, DateTime.parse(info.timestamp).toLocal().toString().length - 7).replaceAll("T", " ");
    int i=0;
    appController.list.insert(i, appController.mydate);
    appController.specialDates = appController.list.map((element) => DateTime.parse(element)).toList();
    i=i+1;