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","."]
docstr: Add string to the history.
docstr_tok: ["Add","string","to","the","history","."]
code: def append_string(self, string: str) -> None:
      "Add string to the history."
      self._loaded_strings.insert(0, string)
      self.store_string(string)
  
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 3 for calling the History obj's underlying member method code with example usage: obj.append_string(string) without return types