code: async function removeMulti(ctx) {
    let { Model } = ctx.state;
    let code = Model.api.removeMulti;
    if (code > _alaska.PUBLIC && !ctx.user) {
      //未登录,需要认证
      ctx.status = 401;
      return;
    }
    ctx.body = {};
    let filters = await Model.createFiltersByContext(ctx);
  
    if (code === _alaska.OWNER) {
      //只允许用户列出自己的资源
      let { userField } = Model.userField;
      // $Flow 这里可以确认ctx.user存在
      filters[userField] = ctx.user._id;
    }
  
    let res = await Model.deleteMany(filters);
  
    ctx.body = {
      removed: res.n
    };
  }
docs: 使用Filters同时删除多条记录