pytest.raises() variation accepting None for cases when no exception is expected

maybe_raises.py

from contextlib import nullcontext
from typing import ContextManager, Optional, Union

import pytest


def maybe_raises(
    exception: Union[type[BaseException], tuple[type[BaseException], ...]]
) -> ContextManager[Optional[pytest.ExceptionInfo[BaseException]]]:
    if exception is None:
        return nullcontext()
    else:
        return pytest.raises(exception)