class_docstr: A sequence of statuses of trials as they progress.
  
  If all trials keep previous status, no snapshot is taken.
docstr: True if all trials are terminated.
docstr_tok: ["True","if","all","trials","are","terminated","."]
code: def all_trials_are_terminated(self) -> bool:
      """True if all trials are terminated."""
      if not self._snapshot:
          return False
      last_snapshot = self._snapshot[-1]
      return all(
          last_snapshot[trial_id] == Trial.TERMINATED
          for trial_id in last_snapshot
      )
  
imports: from collections import defaultdict
  import logging
  import os
  import random
  import time
  from pathlib import Path
  from typing import Dict
  from ray.tune.callback import Callback
  from ray.tune.experiment import Trial
label_desc: Use image node_id 4 for calling the TrialStatusSnapshot obj's underlying member method code with example usage: obj.all_trials_are_terminated() and returns: all, False