from typing import Any


def coerce_list(obj: Any) -> list:
    """
    Takes an object of any type and returns a list.

    If ``obj`` is a list it will be passed back with modification. Otherwise, a
    single-item list containing ``obj`` will be returned.

    :param obj: an object of any type
    :return: a list equal to or containing ``obj``

    """
    return [obj] if not isinstance(obj, list) else obj