code: def __init__(self) -> None:
      # Trial number to corresponding FrozenTrial.
      self.trials: Dict[int, FrozenTrial] = {}
      # A list of trials which do not require storage access to read latest attributes.
      self.finished_trial_ids: Set[int] = set()
      # Cache distributions to avoid storage access on distribution consistency check.
      self.param_distribution: Dict[
          str, distributions.BaseDistribution
      ] = {}
      self.directions: Optional[List[StudyDirection]] = None
      self.name: Optional[str] = None
  
imports: import copy
  import threading
  from typing import Any
  from typing import Callable
  from typing import Container
  from typing import Dict
  from typing import List
  from typing import Optional
  from typing import Sequence
  from typing import Set
  from typing import Tuple
  from typing import Union
  import optuna
  from optuna import distributions
  from optuna._typing import JSONSerializable
  from optuna.storages import BaseStorage
  from optuna.storages._heartbeat import BaseHeartbeat
  from optuna.storages._rdb.storage import RDBStorage
  from optuna.study._frozen import FrozenStudy
  from optuna.study._study_direction import StudyDirection
  from optuna.trial import FrozenTrial
  from optuna.trial import TrialState
label_desc: Use image node_id 1 to create a new _StudyInfo object  with example: obj = _StudyInfo()