code: public static String determineKerasBackend(Map<String, Object> modelConfig, KerasModelConfiguration config) {
          String kerasBackend = null;
          if (!modelConfig.containsKey(config.getFieldBackend())) {
              // TODO: H5 files unfortunately do not seem to have this property in keras 1.
              log.warn("Could not read keras backend used (no "
                      + config.getFieldBackend() + " field found) \n"
              );
          } else {
              kerasBackend = (String) modelConfig.get(config.getFieldBackend());
          }
          return kerasBackend;
      }
docs: Determine Keras backend
  
  @param modelConfig parsed model configuration for keras model
  @param config      basic model configuration (KerasModelConfiguration)
  @return Keras backend string
  @throws InvalidKerasConfigurationException Invalid Keras config