code: public IntronSequence removeIntron(String accession) {
  		for (IntronSequence intronSequence : intronSequenceList) {
  			if (intronSequence.getAccession().getID().equals(accession)) {
  				intronSequenceList.remove(intronSequence);
  				intronSequenceHashMap.remove(accession);
  				return intronSequence;
  			}
  		}
  		return null;
  	}
docs: Remove the intron by accession
  @param accession
  @return intron sequence