code: public static void setLearningRate(ComputationGraph net, String layerName, double newLr) {
          setLearningRate(net, layerName, newLr, null, true);
      }
docs: Set the learning rate for a single layer in the network to the specified value. Note that if any learning rate
  schedules are currently present, these will be removed in favor of the new (fixed) learning rate.<br>
  <br>
  <b>Note</b>: <i>This method not free from a performance point of view</i>: a proper learning rate schedule
  should be used in preference to calling this method at every iteration. Note also that
  {@link #setLearningRate(ComputationGraph, double)} should also be used in preference, when all layers need to be set to a new LR
  
  @param layerName Name of the layer to set the LR for
  @param newLr     New learning rate for a single layers