            $class = $container->getParameterBag()->resolveValue($def->getClass());
            $interface = 'Symfony\Component\EventDispatcher\EventSubscriberInterface';

            if (!is_subclass_of($class, $interface)) {
                if (!class_exists($class, false)) {
                    throw new \InvalidArgumentException(sprintf('Class "%s" used for service "%s" cannot be found.', $class, $id));
                }

                throw new \InvalidArgumentException(sprintf('Service "%s" must implement interface "%s".', $id, $interface));
            }

            $definition->addMethodCall('addSubscriberService', array($id, $class));
        }
The software constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component.