As I am new to php I could'nt fix the following error Fatal error: Call to a member function getClient() on a non-object

class Google_Service_Resource
{

  /** @var Google_Service $service */

  private $service;

  /** @var Google_Client $client */
  private $client;

  /** @var string $serviceName */
  private $serviceName;

  /** @var string $resourceName */
  private $resourceName;

  /** @var array $methods */
  private $methods;

  public function __construct($service, $serviceName, $resourceName, $resource)
  {
    $this->service = new Google_Service($client);
    $this->client = $service->getClient();
    $this->serviceName = $serviceName;
    $this->resourceName = $resourceName;
    $this->methods = isset($resource['methods']) ?
        $resource['methods'] :
        array($resourceName => $resource);
  }