Ionic v5 Add Custom Sound to Local Notification

Hi !

I’m trying to impliment a custom sound to my app ,
but it doesn’t seems to take effect tried to move the file in diffrent folder but notthing changed
I’m using v5 with @ionic-native/local-notifications plugin
Where the cash.mp3 file must be placed ?

  id: 1,
  text: 'Single ILocalNotification',
  sound: 'file://cash.mp3',
  data: { secret: key }

Kind regards