和老師一樣的代碼，運行時候總報這個錯誤，應該怎么解決？

export default {

????data() {

????????return {

????????????inputValue: '',

????????????last: []

????????}

????},

????methods: {

????????handleSubmit () {

????????????this.list.push(this.inputValue)

????????????this.inputValue = ''

????????}

????}

};