code: def test_init(self) -> None:
      c = bcc.RGB(10, 20, 30)
      assert c
      assert c.a == 1.0
      assert c.r == 10
      assert c.g == 20
      assert c.b == 30
  
      c = bcc.RGB(10, 20, 30, 0.3)
      assert c
      assert c.a == 0.3
      assert c.r == 10
      assert c.g == 20
      assert c.b == 30
  
imports: from __future__ import annotations
  import pytest
  import bokeh.colors.color
label_desc: Use image node_id 1 for calling the Test_RGB obj's underlying member method code with example usage: obj.test_init() without return types