}

  // NOTE: Because negative paddings are allowed, we assert that if
  // `parent_pad < 0` then `child_pad <= 0` The effect of the negative pad is to
  // remove values, so for example if we have parent_pad = - 1, child_pad = 1
  // the merged pad will not change anything, while the un-merged will remove a
  // value, then insert a 0 at its place. This only holds for low and high pads,