code: def test_BGR(self):
      self.assert_unpack(
          "BGR;15", "BGR;15", 3, (8, 131, 0), (24, 0, 8), (41, 131, 8)
      )
      self.assert_unpack(
          "BGR;16", "BGR;16", 3, (8, 64, 0), (24, 129, 0), (41, 194, 0)
      )
      self.assert_unpack(
          "BGR;24", "BGR;24", 3, (1, 2, 3), (4, 5, 6), (7, 8, 9)
      )
  
imports: from __future__ import annotations
  import sys
  import pytest
  from PIL import Image
label_desc: Use image node_id 9 for calling the TestLibUnpack obj's underlying member method code with example usage: obj.test_BGR() without return types