def command_line_option_to_keyword(option):
    """ Convert the command line version of the option to a keyword.

    Parameters
    ----------
    option: string
        The "long" command line option version

    Returns
    -------
    keyword: string
        The "keyword" version of the option. Namely, the initial "--" is
        removed and all internal "-"s are replaced with "_"s.
    """
    # first, remove the initial "--"
    option = option[2:]
    
    # and replace "-" with "_"
    option = option.replace("-", "_")
    
    return option