class MyList extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return new Column(
      children: [
        new ListTile(
          leading: new MyBullet(),
          title: new Text('My first line'),
        ),
        new ListTile(
          leading: new MyBullet(),
          title: new Text('My second line'),
        )
      ],
    );
  }
}
class MyBullet extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return new Container(
    height: 20.0,
    width: 20.0,
    decoration: new BoxDecoration(
    color: Colors.black,
    shape: BoxShape.circle,
  ),
  );
  }
}