new_contents: #!/usr/bin/env python3
  import argparse
  
  cli_parser = argparse.ArgumentParser()
  cli_subparsers = cli_parser.add_subparsers(help='sub-command help')
  
  # Create the parser for the `mirror` command
  cli_parser_mirror = cli_subparsers.add_parser('mirror',
                                                help='update a local mirror')
  cli_parser_mirror.add_argument('-d', '--dir',
                                 type=str,
                                 nargs=1,
                                 default=None,
                                 help='directory to download to')
  cli_parser_mirror.add_argument('-t', '--type',
                                 type=str,
                                 nargs='+',
                                 choices=['draft',
                                          'iana',
                                          'iesg',
                                          'charter',
                                          'status',
                                          'rfc'],
                                 default='everything',
                                 help='type(s) of files to download')
  
  cli_args = cli_parser.parse_args()
  
subject: Implement argparse for `mirror`