Issue #3321318 by NivethaSubramaniyan, queenvictoria, szeidler: WSOD on...

use Drupal\media_fotoweb\OAuth2\Persistence\ApiTokenPersistence;

use Drupal\media_fotoweb\OAuth2\Persistence\UserTokenPersistence;

use kamermans\OAuth2\OAuth2Handler;

use Psr\Container\ContainerInterface;

/**

 * FotowebClient for configuration of client in fotoweb.

      }

      $configuration['persistenceProvider'] = $tokenPersistence;

    }

    // If we don't have a server yet we can't create a client.

    if (!$configuration['baseUrl']) {

      \Drupal::messenger()->addMessage(

        $this->t("Until a server is added we can't create the configuration."),

        'warning'

      );

      return;

    }

    $this->setConfiguration($configuration);

    $this->client = new FotowebAPIClient($configuration);

  }