class Programmer extends Human {
  constructor(name, age, languages) {
    super(name, age);
    this.availableLanguages = languages;
  }
  showAvailableLanguages() {
    console.log(this.availableLanguages);
  }
}
const programmer = new Programmer('제로초', 29, ['html', 'css', 'js'],);
programmer.showAvailableLanguages(); // ['html', 'css', 'js']