code: public static IActivation mapToIActivation(String kerasActivation, KerasLayerConfiguration conf)
              throws UnsupportedKerasConfigurationException {
          Activation activation = mapToActivation(kerasActivation, conf);
          return activation.getActivationFunction();
      }
docs: Map Keras to DL4J activation functions.
  
  @param kerasActivation String containing Keras activation function name
  @return DL4J activation function