docs: def log_level_type(arg):
  	"""An argparse type representing a logging level."""
  	if not arg.upper() in ('NOTSET', 'DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'):
  		raise argparse.ArgumentTypeError("{0} is not a valid log level".format(repr(arg)))
  	return getattr(logging, arg.upper())