class_docstr: An object that stores necessary information for saving and loading
  checkpoints.
  
  Args:
      attack_args (textattack.AttackArgs): Arguments of the original attack
      attack_log_manager (textattack.loggers.AttackLogManager): Object for storing attack results
      worklist (deque[int]): List of examples that will be attacked. Examples are represented by their indicies within the dataset.
      worklist_candidates (int): List of other available examples we can attack. Used to get the next dataset element when `attack_n=True`.
      chkpt_time (float): epoch time representing when checkpoint was made
docstr: Check that the checkpoint has no duplicates and is consistent.
docstr_tok: ["Check","that","the","checkpoint","has","no","duplicates","and","is","consistent","."]
code: def _verify(self):
      """Check that the checkpoint has no duplicates and is consistent."""
      assert self.num_remaining_attacks == len(
          self.worklist
      ), "Recorded number of remaining attacks and size of worklist are different."
  
      results_set = {
          result.original_text
          for result in self.attack_log_manager.results
      }
      assert (
          len(results_set) == self.results_count
      ), "Duplicate `AttackResults` found."
  
imports: import copy
  import datetime
  import os
  import pickle
  import time
  import textattack
  from textattack.attack_results import FailedAttackResult, MaximizedAttackResult, SkippedAttackResult, SuccessfulAttackResult
  from textattack.shared import logger, utils
label_desc: Use image node_id 13 for calling the AttackCheckpoint obj's underlying member method code with example usage: obj._verify() without return types