code: def center_crop(im, min_sz=None):
      
      r,c,*_ = im.shape
      if min_sz is None: min_sz = min(r,c)
      start_r = math.ceil((r-min_sz)/2)
      start_c = math.ceil((c-min_sz)/2)
      return crop(im, start_r, start_c, min_sz)
docs: Return a center crop of an image