code: def checkerboard():
      """Checkerboard image.
  
      Checkerboards are often used in image calibration, since the
      corner-points are easy to locate.  Because of the many parallel
      edges, they also visualise distortions particularly well.
  
      Returns
      -------
      checkerboard : (200, 200) uint8 ndarray
          Checkerboard image.
      """
      return _load("data/chessboard_GRAY.png")
  
imports: import numpy
  import shutil
  from ..util.dtype import img_as_bool
  from ._registry import registry, registry_urls
  from ..None import __version__
  import os.path
  import os
label_desc: Use image node_id 16 for calling a global function with example usage: checkerboard() and returns: _load