code: def get_layer(self, x, layer, **kwargs):
      
      return self.fprop(x, **kwargs)[layer]
docs: Return a layer output.
      :param x: tensor, the input to the network.
      :param layer: str, the name of the layer to compute.
      :param **kwargs: dict, extra optional params to pass to self.fprop.
      :return: the content of layer `layer`