Fatal error: Uncaught Error: Class 'Illuminate\Database\Eloquent\Relations\Relation' not found in D:\xampp\htdocs\api_patient\vendor\illuminate\database\Eloquent\Relations\BelongsToMany.php:16 Stack trace: #0 {main} thrown in D:\xampp\htdocs\api_patient\vendor\illuminate\database\Eloquent\Relations\BelongsToMany.php on line 16