code: def test_float_plus(self):
      self._dll.tf_bf.restype = c_float
      self._dll.tf_bf.argtypes = (c_byte, c_float)
      self.assertEqual(self._dll.tf_bf(0, -42.0), -14.0)
      self.assertEqual(self.S(), -42)
  
imports: import unittest
  from ctypes import *
  from ctypes.test import need_symbol
  import _ctypes_test
label_desc: Use image node_id 24 for calling the CFunctions obj's underlying member method code with example usage: obj.test_float_plus() without return types