new_contents: import argparse
  import logging
  import sys
  
  import bandoleers
  
  
  class ArgumentParser(argparse.ArgumentParser):
      """
      Implements some common command-line behaviors.
  
      This is a slightly extended version of the standard
      :class:`argparse.ArgumentParser` class that does three
      things for you:
  
      * exits with a non-zero status when help is shown
      * implements --quiet and --verbose mutually exclusive
        options that call :meth:`logging.Logger.setLevel` on
        the root logger
      * adds a --version flag
  
      """
  
      def __init__(self, *args, **kwargs):
          super(ArgumentParser, self).__init__(*args, **kwargs)
          output_control = self.add_mutually_exclusive_group()
          output_control.add_argument('-q', '--quiet',
                                      action='store_true', default=False,
                                      help='disable non-failure output')
          output_control.add_argument('-v', '--verbose',
                                      action='store_true', default=False,
                                      help='show diagnostic output')
          self.add_argument('--version', action='version',
                            version='%(prog)s {}'.format(bandoleers.__version__))
  
      def parse_args(self, *args, **kwargs):
          result = super(ArgumentParser, self).parse_args(*args, **kwargs)
          if result.verbose:
              logging.getLogger().setLevel(logging.DEBUG)
          if result.quiet:
              logging.getLogger().setLevel(logging.ERROR)
          return result
  
      def print_usage(self, file=None):
          stream = file or sys.stdout
          stream.write(self.format_usage())
          sys.exit(64)
  
      def print_help(self, file=None):
          stream = file or sys.stdout
          stream.write(self.format_help())
          sys.exit(64)
  
subject: Add extended version of argparse.ArgumentParser.