code: static Positions newPositions(Matches matches, int position) {
  		if (matches == null) throw new IllegalArgumentException("null matches");
  		if (position < 0L) throw new IllegalArgumentException();
  		//TODO consider restoring dedicated size accessor on matches
  		if (position > matches.store().size()) throw new IllegalArgumentException();
  		return new BitStorePositions(matches, false, position);
  	}
docs: available via default BitStore method