code: def test_custom_func2():
      assert m.custom_function2(3) == 27
      assert m.roundtrip(m.custom_function2)(3) == 27
  
file_path: coremltools/deps/pybind11/tests/test_callbacks.py
imports: import time
  from threading import Thread
  import pytest
  import env
  from pybind11_tests import callbacks
label_desc: Use image node_id 14 for calling a global function with example usage: test_custom_func2() without return types