code: def test_default(self):
      output = look_up_option("not here", {"a", "b"}, default=None)
      self.assertEqual(output, None)
  
file_path: MONAI/tests/test_look_up_option.py
imports: from __future__ import annotations
  import unittest
  from enum import Enum
  from parameterized import parameterized
  from monai.utils import StrEnum, look_up_option
label_desc: Use image node_id 2 for calling the TestLookUpOption obj's underlying member method code with example usage: obj.test_default() without return types