build method Null safety

Implementation

@override
/// It returns a Container widget with a red circle and a text inside it.
///
/// Args:
///   context (BuildContext): The context of the widget.
///
/// Returns:
///   A Container with a red background and a white text with the number of notifications.
Widget build(BuildContext context) {
  return Container(
    width: 35.0,
    height: 35.0,
    decoration: new BoxDecoration(
      color: Colors.red,
      shape: BoxShape.circle,
    ),
    child: Center(child: Text(notification.toString(), style: const TextStyle(fontSize: 24, color: Colors.white, fontWeight: FontWeight.bold),),),
  );
}