code: @Override
      public BELAnnotation convert(List<Annotation> a) {
          if (a == null) {
              return null;
          }
  
          List<String> values = new ArrayList<String>();
          AnnotationDefinition ad = null;
          for (int i = 0; i < a.size(); i++) {
              Annotation ann = a.get(i);
              if (i == 0) {
                  ad = ann.getDefinition();
              } else if (ad != null && !ad.equals(ann.getDefinition())) {
                  throw new IllegalStateException(
                          "annotations must have equal definitions.");
              }
  
              values.add(ann.getValue());
          }
  
          return new BELAnnotation(badc.convert(ad), values);
      }
docs: {@inheritDoc}