code: @Override
  	public AbstractSequence<NucleotideCompound> getSequence(String sequence, long index ) throws CompoundNotFoundException, IOException {
  		SequenceFileProxyLoader<NucleotideCompound> sequenceFileProxyLoader = new SequenceFileProxyLoader<NucleotideCompound>(
  				file,
  				sequenceParser,
  				index,
  				sequence.length(),
  				compoundSet);
  		return new RNASequence(sequenceFileProxyLoader, compoundSet);
  	}
docs: Even though we are passing in the sequence we really only care about the length of the sequence and the offset
  index in the fasta file.
  @param sequence
  @param index
  @return
  @throws CompoundNotFoundException
  @throws IOException