code: def test_rgb_to_hsl_part_15():
      """Test rgb to hsl color function"""
      # assert rgb_to_hsl(0, 0, 0) == (120, 100, 0)
      assert rgb_to_hsl(0, 51, 0) == (120, 100, 10)
      assert rgb_to_hsl(0, 102, 0) == (120, 100, 20)
      assert rgb_to_hsl(0, 153, 0) == (120, 100, 30)
      assert rgb_to_hsl(0, 204, 0) == (120, 100, 40)
      assert rgb_to_hsl(0, 255, 0) == (120, 100, 50)
      assert rgb_to_hsl(51, 255, 51) == (120, 100, 60)
      assert rgb_to_hsl(102, 255, 102) == (120, 100, 70)
      assert rgb_to_hsl(153, 255, 153) == (120, 100, 80)
      assert rgb_to_hsl(204, 255, 204) == (120, 100, 90)
  
imports: from __future__ import division
  from pygal.colors import darken, desaturate, hsl_to_rgb, lighten, parse_color, rgb_to_hsl, rotate, saturate, unparse_color
label_desc: Use image node_id 39 for calling a global function with example usage: test_rgb_to_hsl_part_15() without return types