code: protected function getClient()
      {
          if (!($this->client instanceof Client)) {
              $handlerStack = HandlerStack::create();
              $handlerStack = $this->withOAuth2MiddleWare($handlerStack);
              $this->client = new Client([
                  'handler' => $handlerStack,
                  'auth' => 'oauth2',
                  'base_uri' => $this->basepath,
                  'headers' => [
                      'Accept' => 'application/json',
                      'Content-type' => 'application/json',
                      'User-Agent' => 'qbank3api-phpwrapper/2 (qbankapi: 1; swagger: 1.1)',
                  ],
                  'verify' => $this->verifyCertificates,
              ]);
  
              $this->logger->debug('Guzzle client instantiated.', ['basepath' => $this->basepath]);
          }
  
          return $this->client;
      }
docs: Gets the Guzzle client instance used for making calls.
  
  @return Client