code: def test_get_custom_names(self):
      names = _get_custom_layer_names(self.spec)
      self.assertEqual(names, {"name1", "name2"})
  
imports: import unittest
  import numpy
  import tempfile
  import pytest
  import shutil
  import os
  import coremltools
  from coremltools._deps import _HAS_KERAS_TF, MSG_KERAS1_NOT_FOUND
  from coremltools._deps import _HAS_TF, MSG_TF1_NOT_FOUND
  from coremltools.models.utils import _get_custom_layer_names, _replace_custom_layer_name, _macos_version, _is_macos
  from coremltools.proto import Model_pb2
label_desc: Use image node_id 2 for calling the CustomLayerUtilsTest obj's underlying member method code with example usage: obj.test_get_custom_names() without return types