protected function initialiseClient(array $config = [])
    {
        if (!isset($config['handler']) || !$config['handler'] instanceof HandlerStack) {
            $handlerStack = HandlerStack::create(new CurlHandler());
            $handlerStack->push(
                Middleware::retry(
                    $this->retryDecider()
                )
            );

            $config['handler'] = $handlerStack;
        }

        return new Client($config);
    }