code: public Pair<String> getCrystalIds() {
  		return new Pair<>(
  			moleculeIds.getFirst()+transforms.getFirst().getTransformId()+transforms.getFirst().getCrystalTranslation(),
  			moleculeIds.getSecond()+transforms.getSecond().getTransformId()+transforms.getSecond().getCrystalTranslation());
  	}
docs: Returns a pair of identifiers for each of the 2 member molecules that
  identify them uniquely in the crystal:
  &lt;molecule id (asym unit id)&gt;+&lt;operator id&gt;+&lt;crystal translation&gt;
  @return