def gist_namer(art_title, num):
    """
    Create formatted gist name to help with grouping gists
    Parameters
    ----------
    art_title : str
        defaults to the notebook name
    num: int
        gist count for this article e.g. first gist of article is 0
    """
    # lower case and snake_case the whole thing
    title = art_title.lower().replace(" ", "_")
    title += str(num)
    return title