code: def test_int_callback(self):
      args = []
  
      def func(arg):
          args.append(arg)
          return arg
  
      cb = CFUNCTYPE(None, MyInt)(func)
  
      self.assertEqual(None, cb(42))
      self.assertEqual(type(args[-1]), MyInt)
  
      cb = CFUNCTYPE(c_int, c_int)(func)
  
      self.assertEqual(42, cb(42))
      self.assertEqual(type(args[-1]), int)
  
file_path: cpython/Lib/test/test_ctypes/test_simplesubclasses.py
imports: import unittest
  from ctypes import Structure, CFUNCTYPE, c_int, _SimpleCData
  from ._support import _CData, PyCSimpleType, Py_TPFLAGS_DISALLOW_INSTANTIATION, Py_TPFLAGS_IMMUTABLETYPE
label_desc: Use image node_id 5 for calling the Test obj's underlying member method code with example usage: obj.test_int_callback() and returns: arg