code: def test_opt(self):
      opt = {"x": 0}
      opt = Opt(opt)
      opt["x"] += 1
      opt["x"] = 10
      self.assertEqual(
          opt.history[0][0], "x", "History not set properly"
      )
      self.assertEqual(opt.history[0][1], 1, "History not set properly")
      self.assertEqual(
          opt.history[1][0], "x", "History not set properly"
      )
      self.assertEqual(
          opt.history[1][1], 10, "History not set properly"
      )
  
      opt_copy = deepcopy(opt)
      self.assertEqual(
          opt_copy.history[0][1], 1, "Deepcopy history not set properly"
      )
      self.assertEqual(
          opt_copy.history[1][1],
          10,
          "Deepcopy history not set properly",
      )
  
imports: from parlai.core.opt import Opt
  from parlai.utils.misc import Timer, round_sigfigs, set_namedtuple_defaults, nice_report
  import parlai.utils.strings
  from copy import deepcopy
  import random
  import time
  import unittest
  from parlai.utils.data import DatatypeHelper
  from parlai.utils.curated_response import generate_init_prompot, generate_safe_response
label_desc: Use image node_id 5 for calling the TestUtils obj's underlying member method code with example usage: obj.test_opt() without return types