code: def slice_create(center, block, start=0, stop=None):
      '''Return an slice with a symmetric region around center.'''
  
      do = coor_to_pix_1d(center - block)
      up = coor_to_pix_1d(center + block)
  
      l = max(start, do)
  
      if stop is not None:
          h = min(up + 1, stop)
      else:
          h = up + 1
  
      return slice(l, h, 1f slice_create(center, block, start=0, stop=None):
      '''Return an slice with a symmetric region around center.'''
  
      do = coor_to_pix_1d(center - block)
      up = coor_to_pix_1d(center + block)
  
      l = max(start, do)
  
      if stop is not None:
          h = min(up + 1, stop)
      else:
          h = up + 1
  
      return slice(l, h, 1)
docs: Return an slice with a symmetric region around center.