code: public void onError(Cli cli, Namespace namespace, Throwable e) {
          e.printStackTrace(cli.getStdErr());
      }
docs: Method is called if there is an issue parsing configuration, setting up the
  environment, or running the command itself. The default is printing the stacktrace
  to facilitate debugging, but can be customized per command.
  
  @param cli contains the streams for stdout and stderr
  @param namespace the parsed arguments from the commandline
  @param e The exception that was thrown when setting up or running the command