code: def testPunctuationCharsReadOnly(self):
      punctuation_chars = "/|$%^"
      shlex_instance = shlex.shlex(punctuation_chars=punctuation_chars)
      self.assertEqual(
          shlex_instance.punctuation_chars, punctuation_chars
      )
      with self.assertRaises(AttributeError):
          shlex_instance.punctuation_chars = False
  
imports: import io
  import itertools
  import shlex
  import string
  import unittest
label_desc: Use image node_id 21 for calling the ShlexTest obj's underlying member method code with example usage: obj.testPunctuationCharsReadOnly() without return types