代码：

  const _ = db.command

  const $ = _.aggregate

var time=new Date()

  db.collection('chatroom')

      .aggregate()

      .match({

      sendTime: _.gt(time)

      })

错误信息：

Error: errCode: -501007 invalid parameters | errMsg: [InvalidParameter] Check request parameter fail. Please check your request, but if the problem cannot be solved, contact us.