from collections.abc import Iterable
from typing import Any


def _to_list(x: list[Any] | tuple[Any] | Any) -> list[Any] | tuple[Any]:
    """Converts x to a list if it is not already a list or tuple."""
    if isinstance(x, (list | tuple)):
        return x
    return [x]


def _flatten_list(x: Iterable[Iterable[Any]]) -> list[Any]:
    """Flattens a list of lists."""
    return [item for sublist in x for item in sublist]