code: func GetInstanceProviderID(ctx context.Context, cloud Interface, nodeName types.NodeName) (string, error) {
  	instances, ok := cloud.Instances()
  	if !ok {
  		return "", fmt.Errorf("failed to get instances from cloud provider")
  	}
  	instanceID, err := instances.InstanceID(ctx, nodeName)
  	if err != nil {
  		return "", fmt.Errorf("failed to get instance ID from cloud provider: %v", err)
  	}
  	return cloud.ProviderName() + "://" + instanceID, nil
  }
docs: // GetInstanceProviderID builds a ProviderID for a node in a cloud.