code: def _write_imgdata(img, data, tr, x=0, y=0):
          
          for pixel, (x1, y1) in zip(data, tr):
              img.putpixel((x + x1, y + y1), pixel)
          return img
docs: Write image data.
  
          Parameters
          ----------
          img : `PIL.Image.Image`
              Image.
          data : `iterable` of `int`
              Image data.
          tr : `markovchain.image.traversal.Traversal`
              Image traversal.
          x : `int`
              X offset.
          y : `int`
              Y offset.