Flutter FlatButton is deprecated – alternative solution with width and height

I followed the guide here: https://flutter.dev/docs/release/breaking-changes/buttons.

_buttonPreview(double _height, double _width) {
  final ButtonStyle flatButtonStyle = TextButton.styleFrom(
    minimumSize: Size(_width, _height),
    backgroundColor: Colors.grey,
    padding: EdgeInsets.all(0),
  );
  return TextButton(
    style: flatButtonStyle,
    onPressed: () {},
    child: Text(
      "some text",
      style: TextStyle(color: Colors.white),
    ),
  );
}