class_docstr: Abstract class for the checkpoint storage component.
  
  A checkpoint storage implementations must provide mechanisms to store, list,
  and load checkpoints from a persistent storage. Instances of this class are
  used by the :class:`CheckpointPlugin` strategy plugin.
docstr: Checks if a checkpoint exists
  
  :param checkpoint_name: The name of the checkpoint to check.
  :return: True if it exists.
docstr_tok: ["Checks","if","a","checkpoint","exists",":","param","checkpoint_name",":","The","name","of","the","checkpoint","to","check",".",":","return",":","True","if","it","exists","."]
code: def checkpoint_exists(self, checkpoint_name: str) -> bool:
      """
      Checks if a checkpoint exists
  
      :param checkpoint_name: The name of the checkpoint to check.
      :return: True if it exists.
      """
      pass
  
file_path: avalanche/avalanche/training/plugins/checkpoint.py
imports: from abc import ABC, abstractmethod
  from typing import Union, Callable, IO, Any, Dict, Optional, Iterable, BinaryIO
  import torch
  from avalanche._annotations import deprecated
  from avalanche.core import BaseSGDPlugin
  from avalanche.training.templates import BaseSGDTemplate
label_desc: Use image node_id 4 for calling the CheckpointStorage obj's underlying member method code with example usage: obj.checkpoint_exists(checkpoint_name) without return types