docstr: Callable that returns the current `Size`, required by Vt100_Output.
docstr_tok: ["Callable","that","returns","the","current","`","Size","`",",","required","by","Vt100_Output","."]
code: def _get_size(self) -> Size:
      """
      Callable that returns the current `Size`, required by Vt100_Output.
      """
      if self._chan is None:
          return Size(rows=20, columns=79)
      else:
          (
              width,
              height,
              pixwidth,
              pixheight,
          ) = self._chan.get_terminal_size()
          return Size(rows=height, columns=width)
  
imports: from __future__ import annotations
  import asyncio
  import traceback
  from asyncio import get_running_loop
  from typing import Any, Callable, Coroutine, TextIO, cast
  import asyncssh
  from prompt_toolkit.application.current import AppSession, create_app_session
  from prompt_toolkit.data_structures import Size
  from prompt_toolkit.input import PipeInput, create_pipe_input
  from prompt_toolkit.output.vt100 import Vt100_Output
label_desc: Use image node_id 2 for calling the PromptToolkitSSHSession obj's underlying member method code with example usage: obj._get_size() and returns: Size, Size