code: def parse_options():
      
      parser = argparse.ArgumentParser(description='Video downloader by radzak.',
                                       prog='RTVdownloader')
      urls_group = parser.add_mutually_exclusive_group(required=True)
      urls_group.add_argument('urls',
                              type=str,
                              metavar='URL',
                              default=[],
                              nargs='*',
                              help='urls of sites containing videos you wish to download'
                              )
  
      urls_group.add_argument('-f',
                              type=argparse.FileType('r'),
                              dest='files',
                              metavar='FILE',
                              default=[],
                              nargs='*',
                              help='text file with urls of sites containing videos you '
                                   'wish to download '
                              )
  
      urls_group.add_argument('-o',
                              type=str,
                              dest='onetabs',
                              metavar='ONETAB',
                              default=[],
                              nargs='*',
                              help='onetab links containing urls of the videos you wish to download'
                              )
  
      options = DEFAULT_OPTIONS
  
      # TODO: add dir option that defaults to the DEFAULT_OPTIONS['dl_path']
  
      args = parser.parse_args()
      return options, args
docs: Parse command line arguments.
  
      Returns:
          options, args