code: private static void checkAttachmentPoint(Monomer mon, String str) throws AttachmentException {
  		if (!(mon.getAttachmentListString().contains(str))) {
  			if (!(str.equals("?") || str.equals("pair")) && !mon.getAlternateId().equals("?")) {
  				LOG.info("Attachment point for source is not there");
  				throw new AttachmentException("Attachment point for source is not there: " + str);
  			}
  		}
  	}
docs: method to check the attachment point's existence
  
  @param mon
  Monomer
  @param str
  Attachment point
  @throws AttachmentException
  if the Attachment point is not there