code: def fill_round_rect(setter, x, y, w, h, r, color=None, aa=False):
      
      fill_rect(setter, x + r, y, w - 2 * r, h, color, aa)
      _fill_circle_helper(setter, x + w - r - 1, y + r, r,
                          1, h - 2 * r - 1, color, aa)
      _fill_circle_helper(setter, x + r, y + r, r, 2, h - 2 * r - 1, color, aa)
docs: Draw solid rectangle with top-left corner at x,y, width w, height h,
      and corner radius r