Flutter error: Unable to load asset: "assets/lib/assets/audio/2.wav"

I want to play audio and I use audioplayers package. I got this error that said can't find my audio file. I know that has something to do with pubspec.yaml file. I read the same questions and topics and none of them worked for me.

I think the problem is with the way I address my audio file in pubspec. I have a lot of images there and they work just fine.

here is my code:

ElevatedButton(
   child: Text('Click me'),
   onPressed: () {
     final player = AudioPlayer();
     player.play(AssetSource(
         'lib/assets/audio/2.wav'));
     

my pubspec file:(the last one is my audio file)

assets:
- lib/assets/img/tab_1.png
- lib/assets/img/tab_1s.png
- lib/assets/img/tab_2.png
- lib/assets/img/tab_2s.png
- lib/assets/img/tab_3.png
- lib/assets/img/tab_3s.png
- lib/assets/img/tab_4.png
- lib/assets/img/tab_4s.png
- lib/assets/img/toman1.png
- lib/assets/img/sp1.jpg
- lib/assets/img/sp2.jpg
- lib/assets/img/sp3.jpg
- lib/assets/img/sp4.jpg
- lib/assets/img/sp5.jpg
- lib/assets/img/header_home_quiz.jpg
- lib/assets/img/animal.jpg
- lib/assets/img/gaav.jpg
- lib/assets/img/sad.png
- lib/assets/img/happy.png
- lib/assets/img/cow.jpg
- lib/assets/img/cat.jpg
- lib/assets/img/dog.jpg
- lib/assets/img/duck.jpg
- lib/assets/img/goose.jpg
- lib/assets/img/lion.jpg
- lib/assets/img/wolf.jpg
- lib/assets/img/mouse.jpg
- lib/assets/img/hen.jpg
- lib/assets/img/roster.jpg
- lib/assets/img/tiger.jpg
- lib/assets/img/snake.jpg
- lib/assets/audio/1.mp3
- lib/assets/audio/2.wav

my folder root:

folder root

AssetSource include root assets folder by default. You can move your audios to the root level assets>audio. like

Include path on pubspec.yaml and then play audio with adding assets path.

player.play(AssetSource('audio/2.wav'));