code: private static PolymerNotation convertRNAIntoAnalogSequence(PolymerNotation polymer)
  			throws AnalogSequenceException {
  
  		/* change only if it is possible */
  		for (int i = 0; i < polymer.getPolymerElements().getListOfElements().size(); i++) {
  			polymer.getPolymerElements().getListOfElements().set(i,
  					generateMonomerNotationRNA(polymer.getPolymerElements().getListOfElements().get(i)));
  		}
  
  		return polymer;
  	}
docs: method to generate the sequence of a rna PolymerNotation into its natural
  analogue sequence
  
  @param polymer
  PolymerNotation
  @return PolymerNotation with its natural analogue sequence
  @throws AnalogSequenceException
  if the natural analogues MonomerNotations can not be built