create and use a function inside a model to controller

model_function.php

<?php

  class UserModel extends Model
  {
    public function totalUsers() {
      $users = DB::table('users')->get(); 
      return $users->count(); 
    }
  }

  class UserController extends Model 
  {
    public function index() {
      $user = new User; 
      $total_users =  $user->totalUsers(); 
      return "Total registred users ".$total_users;
    }
  }
  
?>