class_docstr: :class:`.History` class that stores all strings in a file.
code: def store_string(self, string: str) -> None:
      # Save to file.
      with open(self.filename, "ab") as f:
  
          def write(t: str) -> None:
              f.write(t.encode("utf-8"))
  
          write("\n# %s\n" % datetime.datetime.now())
          for line in string.split("\n"):
              write("+%s\n" % line)
  
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 FileHistory obj's underlying member method code with example usage: obj.store_string(string) without return types