Object.defineProperty()中get、set為什么不能和writable一起用會報錯

var obj = {}
Object.defineProperty(obj, 'name', {
  configurable: true,
  enumerable: true,
  writable: true,
  value: 2,
  set(value) {
    name = value
  },
  get() {
    return value
  }
})
obj.name = 2
console.log(obj.name)

如上代碼，會報 Cannot both specify accessors and a value or writable attribute 這個錯
求解