如何查询抢占式实例近 30 天内的历史价格

{

    "RequestId":"xxxxxxxxxxxxxx",

    "NextOffset":1000,

    "SpotPrices":

    {

        "SpotPriceType":[

        {

            "IoOptimized":"none",

            "OriginPrice":0.028,

            "NetworkType":"classic",

            "Timestamp":"2017-09-18T11:00:00Z",

            "ZoneId":"cn-hangzhou-c","SpotPrice":0.006,

            "InstanceType":"ecs.t1.xsmall"

            }

        ]

    }

}