Faker\Provider\id_ID\Person::lastName PHP Method

    public function lastName($gender = null)
    {
        if ($gender === static::GENDER_MALE) {
            return static::lastNameMale();
        }
        if ($gender === static::GENDER_FEMALE) {
            return static::lastNameFemale();
        }
        $lastNameRandomElement = static::randomElement(static::$lastNameFormat);
        return $this->generator->parse($lastNameRandomElement);
    }