code: public static Iterator<ResidueNumber> multiIterator(AtomPositionMap map, List<? extends ResidueRange> rrs) {
  		ResidueRange[] ranges = new ResidueRange[rrs.size()];
  		for (int i = 0; i < rrs.size(); i++) {
  			ranges[i] = rrs.get(i);
  		}
  		return multiIterator(map, ranges);
  	}
docs: Returns a new Iterator over every {@link ResidueNumber} in the list of ResidueRanges.
  Stores the contents of {@code map} until the iterator is finished, so calling code should set the iterator to {@code null} if it did not finish.