code: func addKnownTypes(scheme *runtime.Scheme) error {
  	scheme.AddKnownTypes(SchemeGroupVersion,
  		&VolumeSnapshot{},
  		&VolumeSnapshotList{},
  		&VolumeSnapshotData{},
  		&VolumeSnapshotDataList{},
  	)
  	metav1.AddToGroupVersion(scheme, SchemeGroupVersion)
  	return nil
  }
docs: // addKnownTypes adds the set of types defined in this package to the supplied scheme.