class_docstr: Optional base class for Journal storages.
  
  Storage classes implementing this base class may work faster when
  constructing the internal state from the large amount of logs.
class_docstr_tok: ["Optional","base","class","for","Journal","storages",".","Storage","classes","implementing","this","base","class","may","work","faster","when","constructing","the","internal","state","from","the","large","amount","of","logs","."]
docstr: Load snapshot from the backend.
  
  Returns:
      A serialized snapshot (bytes) if found, otherwise :obj:`None`.
docstr_tok: ["Load","snapshot","from","the","backend",".","Returns",":","A","serialized","snapshot","(","bytes",")","if","found",",","otherwise",":","obj",":","`","None","`","."]
code: def load_snapshot(self) -> Optional[bytes]:
      """Load snapshot from the backend.
  
      Returns:
          A serialized snapshot (bytes) if found, otherwise :obj:`None`.
      """
      raise NotImplementedError
  
file_path: optuna/optuna/storages/_journal/base.py
imports: import abc
  from typing import Any
  from typing import Dict
  from typing import List
  from typing import Optional
label_desc: Use image node_id 2 for calling the BaseJournalLogSnapshot obj's underlying member method code with example usage: obj.load_snapshot() without return types