public function subscribe(UserInterface $user, PlanInterface $plan)
{
$subscription = new $this->class();
$subscription->setName($plan->getName())->setCurrency($plan->getCurrency())->setPrice($plan->getPrice())->setDiscount($plan->getDiscount())->setPlan($plan);
$user->addSubscription($subscription);
$this->event_dispatcher->dispatch(SaaSEvents::SUBSCRIBED, new SubscriptionEvent($subscription));
return $subscription;
}