code: public ValidationResult validate(ObjectInfo object) {
          if (object == null) {
              throw new NullPointerException("object may not be null.");
          }
  
          ValidationResult result = new ValidationResult(object);
  
          Collection<String> contentmodels = object.getContentModels();
          if (contentmodels.size() == 0){
              result.addNote(ValidationResultNotation.noContentModel());
              return result;
          }
  
          for (String contentmodel:contentmodels){
              validateAgainstContentModel(result, contentmodel, object);
          }
  
          return result;
      }
docs: Each object is expected to have at least one content model. Validate each
  of the content models.