/**
  * Make a fragment from a signature string.
  *
  * @param signatureString
  * @param count
  */
 public SignatureFragment(int count, String signatureString) {
   super(count);
   this.signatureString = signatureString;
   this.fragmentAtomContainer =
       MoleculeSignature.fromSignatureString(
           signatureString, NoNotificationChemObjectBuilder.getInstance());
 }