interface IG22MasksHolder<A> {
  WidthAndHeight maskSize();
  L<Image2B> maskImages();
  //LPair<Image2B, A> maskImagesWithLabels();
  L<? extends IG22Mask<A>> masks();
  FloatBWImage ghost();
  double certainty();
  default int nMasks() { ret l(masks()); }
}