def extender(baseitems, charstoextend):
    """ This goes through all items all the items in

    :param baseitems: a sequence of strings
    :param charstoextend: a string consisting of the extension characters
    :return: A sequence of strings.
    """
    ourextension = [baseitem+extending for baseitem in baseitems for extending in charstoextend]
    return ourextension