code: func (g *Cloud) GetZoneByNodeName(ctx context.Context, nodeName types.NodeName) (cloudprovider.Zone, error) {
  	instanceName := mapNodeNameToInstanceName(nodeName)
  	instance, err := g.getInstanceByName(instanceName)
  	if err != nil {
  		return cloudprovider.Zone{}, err
  	}
  	region, err := GetGCERegion(instance.Zone)
  	if err != nil {
  		return cloudprovider.Zone{}, err
  	}
  	return cloudprovider.Zone{FailureDomain: instance.Zone, Region: region}, nil
  }
docs: // GetZoneByNodeName implements Zones.GetZoneByNodeName
  // This is particularly useful in external cloud providers where the kubelet
  // does not initialize node data.