Shared via mypy Playground

main.py

from __future__ import annotations
from collections.abc import Sequence
from os import PathLike
from pathlib import Path
from typing import Any, BinaryIO, TextIO, Union

FileDesignator = Union[PathLike[Any], str, bytes]
FileHandle = Union[TextIO, BinaryIO]

input_files: Sequence[FileDesignator]
input_sources: Sequence[FileDesignator | FileHandle]

if input_files:
    input_sources = list(map(Path, input_files))
else:
    input_sources = [sys.stdin]