docs: private static void honorVerboseFlag(final ArgP argp) {
      if (argp.optionExists("--verbose") && !argp.has("--verbose")
          && !argp.has("-v")) {
        // SLF4J doesn't provide any API to programmatically set the logging
        // level of the underlying logging library.  So we have to violate the
        // encapsulation provided by SLF4J.
        for (final Logger logger :
             ((Logger) LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME))
               .getLoggerContext().getLoggerList()) {
          logger.setLevel(Level.WARN);
        }
      }
    }