code: def test_to_hex(self) -> None:
      c = bcc.RGB(10, 20, 30)
      assert c.to_hex(), f"#{c.r:02x}{c.g:02x}{c.b:02x}"
      assert bcc.RGB(10, 20, 30, 0.0).to_hex() == "#0a141e00"
      assert bcc.RGB(10, 20, 30, 0.5).to_hex() == "#0a141e80"
      assert bcc.RGB(10, 20, 30, 0.996).to_hex() == "#0a141efe"
      assert bcc.RGB(10, 20, 30, 1.0).to_hex() == "#0a141e"
  
imports: from __future__ import annotations
  import pytest
  import bokeh.colors.color
label_desc: Use image node_id 8 for calling the Test_RGB obj's underlying member method code with example usage: obj.test_to_hex() without return types