code: public Pair<Chain> getParentChains() {
  		Atom[] firstMol = this.molecules.getFirst();
  		Atom[] secondMol = this.molecules.getSecond();
  		if (firstMol.length==0 || secondMol.length==0) {
  			logger.warn("No atoms found in first or second molecule, can't get parent Chains");
  			return null;
  		}
  
  		return new Pair<Chain>(firstMol[0].getGroup().getChain(), secondMol[0].getGroup().getChain());
  	}
docs: Finds the parent chains by looking up the references of first atom of each side of this interface
  @return