code: public static HELM2Notation readRNA(String notation)
  			throws FastaFormatException, NotationException, ChemistryException, NucleotideLoadingException {
  		HELM2Notation helm2notation = new HELM2Notation();
  		PolymerNotation polymer = new PolymerNotation("RNA1");
  		if (!(FastaFormat.isNormalDirection(notation))) {
  			String annotation = "3'-5'";
  			helm2notation.addPolymer(new PolymerNotation(polymer.getPolymerID(),
  					FastaFormat.generateElementsforRNA(notation, polymer.getPolymerID()), annotation));
  		} else {
  			helm2notation.addPolymer(new PolymerNotation(polymer.getPolymerID(),
  					FastaFormat.generateElementsforRNA(notation, polymer.getPolymerID())));
  		}
  
  		return helm2notation;
  	}
docs: method to read a rna/dna sequence and generate a HELM2Notation object of
  it
  
  @param notation rna/dna sequence
  @return HELM2Notation object
  @throws FastaFormatException
  if the rna/dna sequence is not in the right format
  @throws NotationException
  if the notation object can not be built
  @throws ChemistryException if chemistry engine can not be initialized
  @throws NucleotideLoadingException if nucleotides can not be loaded