为什么不能commit

<script>
    import store from '@/store'
    export default {
        name: "Add",
        store,
        data() {
            return {
                title: '',
                content: ''
            }
        },
        methods: {
            add() {
                store.commit('addItem', {
                    title: this.title,
                    content: this.content
                })
            }
        }
    };
</script>

export default new Vuex.Store({
  state: {
    lists: []
  },
  mutations: {
    addItem(state,add) {
      state.lists.push(add)
    }

},