Symfony\Component\DependencyInjection\Definition::setClass PHP Method

    public function setClass($class)
    {
        $this->class = $class;

        return $this;
    }

 private function loadRegistrationSubscriber(ContainerBuilder $container, array $config)
 {
     $definition = new Definition();
     if (array_key_exists('class', $config)) {
         $definition->setClass($config['class']);
     } else {
         $definition->setClass('Tahoe\\Bundle\\MultiTenancyBundle\\EventSubscriber\\RegistrationSubscriber');
     }
     $definition->addTag('kernel.event_subscriber');
     if (array_key_exists('manager', $config)) {
         $definition->addArgument(new Reference($config['manager']));
     } else {
         $definition->addArgument(new Reference('tahoe.multi_tenancy.registration_manager'));
     }
     if (array_key_exists('router', $config)) {
         $definition->addMethodCall('setRouter', array(new Reference($config['router'])));
     } else {
         $definition->addMethodCall('setRouter', array(new Reference('tahoe.multi_tenancy.tenant_aware_router')));
     }
     if (array_key_exists('redirect_route', $config)) {
         $container->setParameter(sprintf("%s.registration_subscriber.redirect_route", $this->getAlias()), $config['redirect_route']);
     } else {
         // default parameter
         $container->setParameter(sprintf("%s.registration_subscriber.redirect_route", $this->getAlias()), 'dashboard');
     }
     // we add the definition to the container
     $container->setDefinition('tahoe.multi_tenancy.registration_subscriber', $definition);
 }