class_docstr: CheckpointManager is a class abstraction to manage a training job's
  checkpoints/snapshots with different IO and storage.
code: def get_post_training_snapshot_path(self) -> str:
      raise NotImplementedError("Not implemented in interface class")
  
imports: import abc
  from typing import List
  import torch
  from pytext.utils.file_io import PathManager
  from pytext.utils.usage import log_class_usage
label_desc: Use image node_id 6 for calling the PyTextCheckpointManagerInterface obj's underlying member method code with example usage: obj.get_post_training_snapshot_path() without return types