code: private int getBatchNormAxis(Map<String, Object> layerConfig)
              throws InvalidKerasConfigurationException {
          Map<String, Object> innerConfig = KerasLayerUtils.getInnerLayerConfigFromConfig(layerConfig, conf);
          return (int) innerConfig.get(LAYER_FIELD_AXIS);
      }
docs: Get BatchNormalization axis from Keras layer configuration. Currently unused.
  
  @param layerConfig dictionary containing Keras layer configuration
  @return batchnorm axis
  @throws InvalidKerasConfigurationException Invalid Keras config