code: def test_lighten(self) -> None:
      c = bcc.HSL(10, 0.2, 0.2, 0.2)
      c2 = c.lighten(0.2)
      assert c2 is not c
      assert c2.a == 0.2
      assert c2.h == 10
      assert c2.s == 0.2
      assert c2.l == 0.4
  
      c2 = c.lighten(1.2)
      assert c2 is not c
      assert c2.a == 0.2
      assert c2.h == 10
      assert c2.s == 0.2
      assert c2.l == 1.0
  
imports: from __future__ import annotations
  import pytest
  import bokeh.colors.color
label_desc: Use image node_id 4 for calling the Test_Color obj's underlying member method code with example usage: obj.test_lighten() without return types