code: @Override
      public AnnotationDefinition convert(XBELExternalAnnotationDefinition t) {
          if (t == null) {
              return null;
          }
  
          String id = t.getId();
          String url = t.getUrl();
  
          AnnotationDefinition dest = CommonModelFactory.getInstance()
                  .createAnnotationDefinition(id);
          dest.setURL(url);
  
          return dest;
      }
docs: {@inheritDoc}