def add_low_value_good(preferences:list, new_item:str)->list:
    """
    Given preferences on m items,
    add a new item that is "low valued".
    :param preferences: a list of strings representing bundles of goods,  in decreasing order of preference.
    :param new_item: the name of the new item to add.
    :return: the new preference-list.

    >>> add_low_value_good(["xyz","xy","xz",""], "o")
    ['xyzo', 'xyz', 'xyo', 'xy', 'xzo', 'xz', 'o', '']
    """
    result = []
    for bundle in preferences:
        result.append(bundle+new_item)
        result.append(bundle)
    return result