Nelmio\Alice\Bridge\Symfony\DependencyInjection\Configuration::createStringValidatorClosure PHP Метод

    private function createStringValidatorClosure() : \Closure
    {
        return function ($value) {
            if (is_string($value)) {
                return $value;
            }
            throw InvalidArgumentExceptionFactory::createForExpectedConfigurationStringValue($value);
        };
    }