MaterialColor swatchify(MaterialColor color, int value) {
  return MaterialColor(color[value].hashCode, {
    50: color[value],
    100: color[value],
    200: color[value],
    300: color[value],
    400: color[value],
    500: color[value],
    600: color[value],
    700: color[value],
    800: color[value],
    900: color[value],
  });
}

primarySwatch: swatchify(Colors.purple, 900),