class_docstr: Serialized experiment state cache.
  
  ODB with git SHAs as keys. Objects can be either SerializableExp or
  SerializableError.
code: def __init__(self, repo: "Repo"):
      path = os.path.join(repo.tmp_dir, self.CACHE_DIR)
      self.odb = ObjectDB(localfs, path)
  
file_path: dvc/dvc/repo/experiments/cache.py
imports: import os
  from typing import TYPE_CHECKING, Optional, Union
  from dvc.fs import localfs
  from dvc.log import logger
  from dvc_objects.db import ObjectDB
  from .serialize import DeserializeError, SerializableError, SerializableExp
  from .utils import EXEC_TMP_DIR
label_desc: Use image node_id 1 to create a new ExpCache object  with example: obj = ExpCache(repo)