In caffe, it has the option to set the learning multiple for convolution as follows
layer {
  name: "conv1a"
  type: "Convolution"
  bottom: "data"
  top: "conv1a"
  param {
    lr_mult: 1
  }
  param {
    lr_mult: 2
  }
  convolution_param {
    num_output: 64
    kernel_size: 3
    pad: 1
    stride: 1    
    bias_filler {
      type: "constant"
      value: 0
    }
  }
}

In pytorch, how to set the lr_mult for convolutional layer only with SGD? Thanks