def use_correct_indefinite_article(some_noun):
    """
    Given a noun determine whether 'a' or 'an'
    should be used as an indefinite article.
    There are some exceptions, but this is probably
    good enough.

    :param some_noun:
    :return:
    """
    vowels = ('a', 'e', 'i', 'o', 'u')
    if some_noun.lower()[0] in vowels:
        return 'an'
    return 'a'