Computed property "selected_all" was assigned to but it has no setter，在购物车添加完去结算，然后商品列表不显示

这是用python 写一个商城项目 报的错，原因是全选vue报的错

    on_selected_all: function(){
            var selected = !this.selected_all;
            axios.put(this.host + '/cart/selection/', {
                    selected
                }, {
                    responseType: 'json',
                    headers:{
                        'Authorization': 'JWT ' + this.token
                    },
                    withCredentials: true
                })
                .then(response => {
                    for (var i=0; i<this.cart.length;i++){
                        this.cart[i].selected = selected;
                    }
                })
                .catch(error => {
                    console.log(error.response.data);
                })
        },