Updating a map in an array (Dart)

gistfile1.txt

main() {
  List<User> users = [
    User(lastName: "Mesut", firstName: "Ozil"),
    User(lastName: "Becham", firstName: "David"),
    User(lastName: "Samir", firstName: "Nasri"),
    User(lastName: "Arteta", firstName: "Mikel"),
  ];
  User userOLD =  users.firstWhere((user){
    return user.firstName == "Mikel";
  });
  users[users.indexOf(userOLD)] = User(lastName: "ARTETER", firstName: "MIKELLOOO");
  print(users);
}

class User{
  final String firstName;
  final String lastName;

  User({this.firstName, this.lastName});

  @override
  String toString() {
    return 'User{firstName: $firstName, lastName: $lastName}';
  }

}