code: @Override
      public XBELAnnotation convert(Annotation source) {
          if (source == null) return null;
  
          AnnotationDefinition definition = source.getDefinition();
          String refID = definition.getId();
          String value = source.getValue();
  
          XBELAnnotation xa = new XBELAnnotation();
          xa.setRefID(refID);
          xa.setValue(value);
  
          return xa;
      }
docs: {@inheritDoc}