code: def _checker_mixer(slice1,
                     slice2,
                     checker_size=None):
      
  
      checkers = _get_checkers(slice1.shape, checker_size)
      if slice1.shape != slice2.shape or slice2.shape != checkers.shape:
          raise ValueError('size mismatch between cropped slices and checkers!!!')
  
      mixed = slice1.copy()
      mixed[checkers > 0] = slice2[checkers > 0]
  
      return mixed
docs: Mixes the two slices in alternating areas specified by checkers