docs: def _setup_default_handler(progname, fmt=None, datefmt=None, **_):
      """Create a Stream handler (default handler).
  
      Args:
          progname (str): Name of program.
          fmt (:obj:`str`, optional): Desired log format if different than
              the default; uses the same formatting string options
              supported in the stdlib's `logging` module.
          datefmt (:obj:`str`, optional): Desired date format if different
              than the default; uses the same formatting string options
              supported in the stdlib's `logging` module.
  
      Returns:
          (obj): Instance of `logging.StreamHandler`
      """
      handler = logging.StreamHandler()
  
      if not fmt:
          # ex: 2017-08-26T14:47:44.968+00:00 <progname> (<PID>) INFO: <msg>
          fmt_prefix = '%(asctime)s.%(msecs)03dZ '
          fmt_suffix = ' (%(process)d) %(levelname)s: ' + '%(message)s'
          fmt = fmt_prefix + progname + fmt_suffix
      if not datefmt:
          datefmt = '%Y-%m-%dT%H:%M:%S'
  
      formatter = logging.Formatter(fmt=fmt, datefmt=datefmt)
      handler.setFormatter(formatter)
      return handler