def argparse_args(cmd_parser):
    """initialize argparse arguments that the main() function expects"""
    cmd_parser.add_argument('-n', dest='name_filter', nargs='+', metavar='',
        help='Instance tag value filter for the tag key "Name".')
    cmd_parser.add_argument('-r', dest='region_filter', nargs='+', metavar=
        '', help=
        'AWS region(s) to probe for instances. If not set, all whitelisted regions will be probed.'
        )
    cmd_parser.add_argument('-t', dest='tag_filters', nargs='+', action=
        'append', metavar='', help=
        'Instance tag value filter. First value is the tag key, with proceeding value(s) as the tag value(s). If only 1 value given, the tag key itself will be filtered for instead.'
        )
    cmd_parser.add_argument('-i', dest='id_filter', nargs='+', metavar='',
        help='Instance ID filter.')
