private function isEventSubscriber($subscriberClass): bool
    {
        return \is_object($subscriberClass) || (\is_string($subscriberClass) && \class_exists($subscriberClass))
            ? \in_array(EventSubscriber::class, \class_implements($subscriberClass), true)
            : false;
    }
private function isEventSubscriber($subscriberClass): bool
    {
        return \is_object($subscriberClass) || (\is_string($subscriberClass) && \class_exists($subscriberClass))
            ? \in_array(EventSubscriber::class, \class_implements($subscriberClass), true)
            : false;
    }
private function isEventSubscriber ( $ subscriberClass ) : bool { return \ is_object ( $ subscriberClass ) || ( \ is_string ( $ subscriberClass ) && \ class_exists ( $ subscriberClass ) ) ? \ in_array ( EventSubscriber :: class , \ class_implements ( $ subscriberClass ) , true ) : false ; }
Is an event subscriber.

@param $subscriberClass

@return bool
Is an event subscriber .