code: def obj_box_coord_centroid_to_upleft(coord):
      
      if len(coord) != 4:
          raise AssertionError("coordinate should be 4 values : [x, y, w, h]")
  
      x_center, y_center, w, h = coord
      x = x_center - w / 2.
      y = y_center - h / 2.
      return [x, y, w, h]
docs: Convert one coordinate [x_center, y_center, w, h] to [x, y, w, h].
      It is the reverse process of ``obj_box_coord_upleft_to_centroid``.
  
      Parameters
      ------------
      coord : list of 4 int/float
          One coordinate.
  
      Returns
      -------
      list of 4 numbers
          New bounding box.