code: def test__save_modified_value_unchanged(self):
      config_vars = {
          "CC": "gcc-test -pthreads",
      }
      expected_vars = config_vars.copy()
      cv = "CC"
      newvalue = "gcc-test -pthreads"
      _osx_support._save_modified_value(config_vars, cv, newvalue)
      self.assertEqual(expected_vars, config_vars)
  
imports: import os
  import platform
  import stat
  import sys
  import unittest
  from test.support import os_helper
  import _osx_support
label_desc: Use image node_id 9 for calling the Test_OSXSupport obj's underlying member method code with example usage: obj.test__save_modified_value_unchanged() without return types