Наследование: extends Exceptio\Exception
 public static function determineActivityModel() : string
 {
     $activityModel = config('laravel-activitylog.activity_model') != null ? config('laravel-activitylog.activity_model') : Activity::class;
     if (!is_a($activityModel, Activity::class, true)) {
         throw InvalidConfiguration::modelIsNotValid($activityModel);
     }
     return $activityModel;
 }