Javascript分配箭头功能说明

Question

Hello Stack Overflow社区，谁能解释我为什么第一种方法可行，为什么第二种返回未定义？

const o = {
  name: "Bob",
  age: 37,
};


/* First Method */

function info() {
   return "Info: " + this.name + " -> " + this.age;
}

o.info = info;

console.log(o.info()); //Info: Bob -> 37

/* Second Method */

o.info = () => {
   return "Info: " + this.name + " -> " + this.age;
}

console.log(o.info); //Undefined