code: function exitWithError(error) {
      if (error instanceof Error) {
          process.stderr.write(chalk.red(error));
      } else {
          help();
      }
      process.exit(1);
  }
docs: Utility function that exist the process with an
  optional error. If an Error is received, the error
  message is written to stdout, otherwise, the help
  content are displayed.
  
  @param {*} error Either an instance of Error or null