code: def setUp(self):
      self.env = self.enterContext(EnvironmentVarGuard())
      if "POSIXLY_CORRECT" in self.env:
          del self.env["POSIXLY_CORRECT"]
  
file_path: cpython/Lib/test/test_getopt.py
imports: from test.support.os_helper import EnvironmentVarGuard
  import doctest
  import unittest
  import getopt
label_desc: Use image node_id 1 for calling the GetoptTests obj's underlying member method code with example usage: obj.setUp() without return types