将teacher类中的grade方法的值转化为大写,并在读取grade是没有信息,输出nograde
```html
class Teacher {
constructor(options) {
this.name = options.name;
this.age = options.age;
this.course = options.course;
this.score = options.score;
this.grade = options.grade;
}
}
const teacher = new Teacher({
name: "tom",
age: "30",
course: "computer safe",
score: "99",
grade: "grade one",
});
console.log(teacher);
```