How to type $allModels result extension

I have the following simple example of a result extension:

$allModels:{
  $toJson:{
    compute(data){
      return ()=>data
    }
  }
}

$allModels:{
  $toJson:{
    compute(data){
      return ()=>data
    }
  }
}

However on all my modelsI can't even call it. It just says type never has no call signatures

How to type $allModels result extension - Prisma