from typing import TypeVar

from pandas import (
    Categorical,
    CategoricalIndex,
    Series,
)

_CatT = TypeVar("_CatT", bound=Categorical | CategoricalIndex | Series)

def union_categoricals(
    to_union: list[_CatT],
    sort_categories: bool = False,
    ignore_order: bool = False,
) -> Categorical: ...
