docs: public List<C> instantiateClasses(Parameterization config) {
      config = config.descend(this);
      List<C> instances = new ArrayList<>();
      if(getValue() == null) {
        config.reportError(new UnspecifiedParameterException(this));
        return instances; // empty list.
      }
  
      for(Class<? extends C> cls : getValue()) {
        // NOTE: There is a duplication of this code in ObjectListParameter - keep
        // in sync!
        try {
          instances.add(ClassGenericsUtil.tryInstantiate(restrictionClass, cls, config));
        }
        catch(Exception e) {
          config.reportError(new WrongParameterValueException(this, cls.getName(), e.getMessage(), e));
        }
      }
      return instances;
    }