code: def check_type(self, typ, arg):
      PROTO = self.functype.im_func(typ, typ)
      result = PROTO(self.callback)(arg)
      if typ == c_float:
          self.assertAlmostEqual(result, arg, places=5)
      else:
          self.assertEqual(self.got_args, (arg,))
          self.assertEqual(result, arg)
  
      PROTO = self.functype.im_func(typ, c_byte, typ)
      result = PROTO(self.callback)(-3, arg)
      if typ == c_float:
          self.assertAlmostEqual(result, arg, places=5)
      else:
          self.assertEqual(self.got_args, (-3, arg))
          self.assertEqual(result, arg)
  
imports: import functools
  import unittest
  from ctypes import *
  from ctypes.test import need_symbol
  import _ctypes_test
label_desc: Use image node_id 2 for calling the Callbacks obj's underlying member method code with example usage: obj.check_type(typ, arg) without return types