def force_list(value):
    """
    Coerce the input value to a list.

    If `value` is `None`, return an empty list. If it is a single value, create
    a new list with that element on index 0.

    :param value: Input value to coerce.
    :return: Value as list.
    :rtype: list
    """

    if value is None:
        return []
    elif type(value) == list:
        return value
    else:
        return [value]