code: def test_double(self):
      self.check_type(c_double, 3.14)
      self.check_type(c_double, -3.14)
  
imports: import functools
  import unittest
  from ctypes import *
  from ctypes.test import need_symbol
  import _ctypes_test
label_desc: Use image node_id 14 for calling the Callbacks obj's underlying member method code with example usage: obj.test_double() without return types