code: def pure_virtual_func(self):
      pass
  
imports: import multiprocessing
  import sys
  import threading
  import time
  import pytest
  import env
  from pybind11_tests import gil_scoped
label_desc: Use image node_id 2 for calling the ExtendedVirtClass obj's underlying member method code with example usage: obj.pure_virtual_func() without return types