function2

main.dart

void main() {
  var values = [1, 2, 3, 4, 5, 6, 7, 8, 9];
  var newVlues = <int>[];
  var multiply5 = (int value) => newVlues.add(value * 5);
  listOperation(values, multiply5);
  print(newVlues);
}

void listOperation(List<int> list, void Function(int) action) {
  for (var item in list) {
    action(item);
  }
}