def pluralize(num, singular):
    """Return the proper plural version.
    Examples:

    >>> pluralize(2, "meme")
    '2 memes'

    >>> pluralize(1, "thing")
    '1 thing'

    >>> pluralize(1, "class")
    '1 class'

    >>> pluralize(0, "class")
    '0 classes'
    """

    if num == 1:
        return f"{num} {singular}"

    plural_form = singular + ("es" if (singular[-1] == "s") else "s")

    return f"{num} {plural_form}"