/**
  * returns the current plan
  *
  * @param SubscriptionSubscriber $subscriber
  * @param bool $useDefaultPlan
  *
  * @return Plan|null
  */
 public function plan(SubscriptionSubscriber $subscriber, $useDefaultPlan = true)
 {
     $subscription = $this->current($subscriber);
     if (null === $subscription) {
         return $useDefaultPlan ? $this->planRepository->defaultPlan() : null;
     }
     $plan = $subscription->plan;
     return $this->planRepository->find($plan);
 }