code: private ChemComp getEmptyChemComp(String resName){
  		String pdbName = ""; // Empty string is default
  		if (null != resName && resName.length() >= 3) {
  			pdbName = resName.substring(0,3);
  		}
  		final ChemComp comp = new ChemComp();
  		comp.setOne_letter_code("?");
  		comp.setThree_letter_code(pdbName);
  		comp.setPolymerType(PolymerType.unknown);
  		comp.setResidueType(ResidueType.atomn);
  		return comp;
  	}
docs: Return an empty ChemComp group for a three-letter resName.
  @param resName
  @return