code: public void activateNeuralNetworkRules(File modelDir) throws IOException {
      ResourceBundle messages = getMessageBundle(language);
      List<Rule> rules = language.getRelevantNeuralNetworkModels(messages, modelDir);
      userRules.addAll(rules);
    }
docs: Activate rules that depend on pretrained neural network models.
  @param modelDir root dir of exported models
  @since 4.4