class_docstr: Two dimensional buffer of :class:`.Char` instances.
code: def visible_windows(self) -> list[Window]:
      return list(self.visible_windows_to_write_positions.keys())
  
imports: from __future__ import annotations
  from collections import defaultdict
  from typing import TYPE_CHECKING, Callable
  from prompt_toolkit.cache import FastDictCache
  from prompt_toolkit.data_structures import Point
  from prompt_toolkit.utils import get_cwidth
label_desc: Use image node_id 2 for calling the Screen obj's underlying member method code with example usage: obj.visible_windows() and returns: list