class_docstr: Call multiple callbacks at once.
class_docstr_tok: ["Call","multiple","callbacks","at","once","."]
code: def __init__(self, callbacks: List[Callback]):
      self._callbacks = callbacks
  
imports: from abc import ABCMeta
  import glob
  import os
  from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
  import warnings
  from ray.util.annotations import PublicAPI, DeveloperAPI
  from ray.tune.utils.util import _atomic_save, _load_newest_checkpoint
label_desc: Use image node_id 1 to create a new CallbackList object from inherited base classes: Callback with example: obj = CallbackList(callbacks)