Toggle between LIGHT and DARK theme (flutter_neumorphic: ^2.0.0)

I use flutter_neumorphic: ^2.0.0 package to give my app a cool look and I like to add a toggle to switch between LIGHT and DARK. Unfortunately I'm new to coding and I can't do this toggle button by my self, can you help me please.

Thank you

import 'package:babysoundtrips/screens/sound_screen.dart';
import 'package:flutter/material.dart';
import 'package:flutter_neumorphic/flutter_neumorphic.dart';

void main() => runApp(BabySoundTrips());

class BabySoundTrips extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: NeumorphicTheme(
        usedTheme: UsedTheme.LIGHT,
        theme: NeumorphicThemeData(
          baseColor: Color(0xFFFFFFFF),
          lightSource: LightSource.topLeft,
          depth: 10,
        ),
        darkTheme: NeumorphicThemeData(
          baseColor: Color(0xFF3E3E3E),
          lightSource: LightSource.topLeft,
          depth: 6,
        ),
        child: SoundScreen(),
      ),
      initialRoute: SoundScreen.id,
      routes: {
        SoundScreen.id: (context) => SoundScreen(),
      },
    );
  }
}

Here is an example of the toggle button

FlatButton(
  child: Row(
    children: <Widget>[
      Expanded(child: Text("Change theme")),
      Switch(
          value: true,
          onChanged: null),
    ],
  ),
  onPressed: () {
    // handle change value here
  },
);

This snip code needs to embed in the stateful widget and pass the value that you want to change to Switch value, and update this value via my comment "// handle change value here".