code: def testGetFnFailure(self):
      with self.assertRaises(ValueError):
          udf_utils.get_fn({}, "test_fn")
  
imports: import hashlib
  import os
  import subprocess
  import sys
  import tempfile
  from unittest import mock
  import tensorflow
  from tfx.components.util import udf_utils
  from tfx.dsl.components.base import base_component
  from tfx.dsl.components.base import base_executor
  from tfx.dsl.components.base import executor_spec
  from tfx.types import component_spec
  from tfx.utils import import_utils
label_desc: Use image node_id 4 for calling the UdfUtilsTest obj's underlying member method code with example usage: obj.testGetFnFailure() without return types