code: def test_CMYK16(self):
      self.assert_unpack(
          "CMYK", "CMYK;16L", 8, (2, 4, 6, 8), (10, 12, 14, 16)
      )
      self.assert_unpack(
          "CMYK", "CMYK;16B", 8, (1, 3, 5, 7), (9, 11, 13, 15)
      )
      if sys.byteorder == "little":
          self.assert_unpack(
              "CMYK", "CMYK;16N", 8, (2, 4, 6, 8), (10, 12, 14, 16)
          )
      else:
          self.assert_unpack(
              "CMYK", "CMYK;16N", 8, (1, 3, 5, 7), (9, 11, 13, 15)
          )
  
imports: from __future__ import annotations
  import sys
  import pytest
  from PIL import Image
label_desc: Use image node_id 21 for calling the TestLibUnpack obj's underlying member method code with example usage: obj.test_CMYK16() without return types