Pythonのtyping.Literalの選択肢をlistとして渡す方法

以下のように tuple を利用することでうまく定義できます．

from typing import Literal

choices = ["a", "b"]
choices_dict = {"a": 1, "b": 2}

Literal["a", "b"] == Literal[choices]
>>> False

Literal["a", "b"] == Literal[tuple(choices)]
>>> True

Literal["a", "b"] == Literal[choices_dict.keys()]
>>> False

Literal["a", "b"] == Literal[tuple(choices_dict.keys())]
>>> True

参考: Typing dynamically create literal alias from list of valid values