code: def setup_logging(verbosity, filename=None):
      
      levels = [logging.WARNING, logging.INFO, logging.DEBUG]
      level = levels[min(verbosity, len(levels) - 1)]
      logging.root.setLevel(level)
  
      fmt = logging.Formatter('%(asctime)s %(levelname)-12s %(message)-100s '
                              '[%(filename)s:%(lineno)d]')
      hdlr = logging.StreamHandler()  # stderr
      hdlr.setFormatter(fmt)
      logging.root.addHandler(hdlr)
  
      if filename:
          hdlr = logging.FileHandler(filename, 'a')
          hdlr.setFormatter(fmt)
          logging.root.addHandler(hdlr)
docs: Configure logging for this tool.