code: private double getMomentumFromConfig(Map<String, Object> layerConfig) throws InvalidKerasConfigurationException {
          Map<String, Object> innerConfig = KerasLayerUtils.getInnerLayerConfigFromConfig(layerConfig, conf);
          if (!innerConfig.containsKey(LAYER_FIELD_MOMENTUM))
              throw new InvalidKerasConfigurationException(
                      "Keras BatchNorm layer config missing " + LAYER_FIELD_MOMENTUM + " field");
          return (double) innerConfig.get(LAYER_FIELD_MOMENTUM);
      }
docs: Get BatchNormalization momentum parameter from Keras layer configuration.
  
  @param layerConfig dictionary containing Keras layer configuration
  @return momentum
  @throws InvalidKerasConfigurationException Invalid Keras config