code: def transformer(data, label):
      
      # resize to 64x64
      data = mx.image.imresize(data, 64, 64)
      # transpose from (64, 64, 3) to (3, 64, 64)
      data = mx.nd.transpose(data, (2, 0, 1))
      # normalize to [-1, 1]
      data = data.astype(np.float32)/128 - 1
      # if image is greyscale, repeat 3 times to get RGB image.
      if data.shape[0] == 1:
          data = mx.nd.tile(data, (3, 1, 1))
      return data, label
docs: Get the translation of images