How to use the gulplog.warn function in gulplog

cli.on('requireFail', function(name, error) {
  log.warn(
    ansi.yellow('Failed to load external module'),
    ansi.magenta(name)
  );
  /* istanbul ignore else */
  if (error) {
    log.warn(ansi.yellow(error.toString()));
  }
});

cli.on('requireFail', function(name, error) {
  log.warn(
    ansi.yellow('Failed to load external module'),
    ansi.magenta(name)
  );
  /* istanbul ignore else */
  if (error) {
    log.warn(ansi.yellow(error.toString()));
  }
});

"Packages/Microsoft.MinecraftUWP_8wekyb3d8bbwe/LocalState/games/com.mojang"
        );

        //script task factories
        this.scriptTasks = []; 
        this.behaviorTasks = [];     
        this.resourcesTasks = [];
        this.installBehaviorTasks = [];
        this.installResourcesTasks = [];

        this.outDir = "./built";
        this.scriptsDir = "./src/scripts/";
        this.behaviorDir = "./src/behaviors/";
        this.resourcesDir = "./src/resources/";

        log.warn("------------");
        log.warn("You are using the older V0 version of the toolchain.");
        log.warn("It is recommended that you update to the latest version. Please see the upgrade notes for details");
        log.warn("https://minecraft-addon-tools.github.io/docs/Toolchain/upgrade-notes-v1");
        log.warn("------------");
    }

function noop() {
		if (!taskInfo.name) {
			taskInfo.name = '';
		}
		log.warn('configure:', 'the task "' + taskInfo.name + "\" won't do anything, misspelled a recipe name?");
		return self.create(prefix, taskInfo, {}, self.recipes.noop());
	}

//script task factories
        this.scriptTasks = []; 
        this.behaviorTasks = [];     
        this.resourcesTasks = [];
        this.installBehaviorTasks = [];
        this.installResourcesTasks = [];

        this.outDir = "./built";
        this.scriptsDir = "./src/scripts/";
        this.behaviorDir = "./src/behaviors/";
        this.resourcesDir = "./src/resources/";

        log.warn("------------");
        log.warn("You are using the older V0 version of the toolchain.");
        log.warn("It is recommended that you update to the latest version. Please see the upgrade notes for details");
        log.warn("https://minecraft-addon-tools.github.io/docs/Toolchain/upgrade-notes-v1");
        log.warn("------------");
    }

childExec(exec, undefined, (_err, stdout, stderr) => {
                    if (stderr) logger.warn(stderr)
                    if (stdout) logger.warn(stdout)
                    done()
                })
            })

childExec(exec, undefined, (_err, stdout, stderr) => {
                    if (stderr) logger.warn(stderr)
                    if (stdout) logger.warn(stdout)
                    done()
                })
            })

//script task factories
        this.scriptTasks = []; 
        this.behaviorTasks = [];     
        this.resourcesTasks = [];
        this.installBehaviorTasks = [];
        this.installResourcesTasks = [];

        this.outDir = "./built";
        this.scriptsDir = "./src/scripts/";
        this.behaviorDir = "./src/behaviors/";
        this.resourcesDir = "./src/resources/";

        log.warn("------------");
        log.warn("You are using the older V0 version of the toolchain.");
        log.warn("It is recommended that you update to the latest version. Please see the upgrade notes for details");
        log.warn("https://minecraft-addon-tools.github.io/docs/Toolchain/upgrade-notes-v1");
        log.warn("------------");
    }

);

        //script task factories
        this.scriptTasks = []; 
        this.behaviorTasks = [];     
        this.resourcesTasks = [];
        this.installBehaviorTasks = [];
        this.installResourcesTasks = [];

        this.outDir = "./built";
        this.scriptsDir = "./src/scripts/";
        this.behaviorDir = "./src/behaviors/";
        this.resourcesDir = "./src/resources/";

        log.warn("------------");
        log.warn("You are using the older V0 version of the toolchain.");
        log.warn("It is recommended that you update to the latest version. Please see the upgrade notes for details");
        log.warn("https://minecraft-addon-tools.github.io/docs/Toolchain/upgrade-notes-v1");
        log.warn("------------");
    }

function warn() {
  var taskKeys = Object.keys(tasks);

  if (!taskKeys.length) {
    return;
  }

  var taskNames = taskKeys.map(function(key) {
    return tasks[key];
  }).join(', ');

  process.exitCode = 1;

  log.warn(
    ansi.red('The following tasks did not complete:'),
    ansi.cyan(taskNames)
  );
  log.warn(
    ansi.red('Did you forget to signal async completion?')
  );
}