code: public static String getTypeValue(Class<? extends WindupFrame> clazz)
      {
          TypeValue typeValueAnnotation = clazz.getAnnotation(TypeValue.class);
          if (typeValueAnnotation == null)
              throw new IllegalArgumentException("Class " + clazz.getCanonicalName() + " lacks a @TypeValue annotation");
  
          return typeValueAnnotation.value();
      }
docs: Returns the type discriminator value for given Frames model class, extracted from the @TypeValue annotation.