Create is a stateful widget which receives the postDoc snapshot from another Class.

```
class Create extends StatefulWidget {
  final DocumentSnapshot postDoc;

  Create({this.postDoc});

  @override
  _CreateState createState() => _CreateState();
}

```

The postDoc has a 'contributers' field with its type as List

I want to copy the elements in `widget.postDoc['contributers']` and add another element at the last.

The new list will now be used as value "contributers" field in a new post.

How should I copy widget.postDoc['contributer'] and add element to it?

I've already tried,

```
List<dynamic> contributer;
contributer=widget.postDoc['contributers'];
contributer.add(widget.postDoc['username']);

```

but the contributer is now of fixed-length and new element cannot be added.