/** * Constructor. * * @param string $version * @param string $apiKey * @param string $apiVersion * @return void * @throws \RuntimeException */ public function __construct($version, $apiKey, $apiVersion) { $api_key = $apiKey ?: getenv('STRIPE_API_KEY'); $api_version = $apiVersion ?: getenv('STRIPE_API_VERSION') ?: '2015-03-24'; if (!$api_key) { throw new \RuntimeException('The Stripe API key is not defined!'); } parent::__construct(compact('version', 'api_key', 'api_version')); }