class_docstr: Base ``History`` class.
  
  This also includes abstract methods for loading/storing history.
class_docstr_tok: ["Base","``","History","``","class",".","This","also","includes","abstract","methods","for","loading\/storing","history","."]
code: def __init__(self) -> None:
      # In memory storage for strings.
      self._loaded = False
  
      # History that's loaded already, in reverse order. Latest, most recent
      # item first.
      self._loaded_strings: list[str] = []
  
imports: from __future__ import annotations
  import datetime
  import os
  import threading
  from abc import ABCMeta, abstractmethod
  from asyncio import get_running_loop
  from typing import AsyncGenerator, Iterable, Sequence
label_desc: Use image node_id 1 to create a new History object  with example: obj = History()