Go Json汎用解析について

Json          
package json

import (
   "encoding/json"
   "testing"
)

type (
   Result struct {
      Code    int             `json:"code"`
      Message string          `json:"message"`
      Data    json.RawMessage `json:"data"`
   }

   TickersResult struct {
      Tickers []struct {
         ID              string  `json:"_id"`
         DisplayPairName string  `json:"display_pair_name"`
         Price           float64 `json:"price"`
         Volume          float64 `json:"volume"`
      } `json:"tickers"`
   }

   Student struct {
      Name   string  `json:"name"`
      Class  string  `json:"class"`
      Weight float64 `json:"weight"`
      Age    int     `json:"age"`
   }
   IBean interface{ Tag() }
)

func (*TickersResult) Tag() {}
func (*Student) Tag()       {}

func (r *Result) ParseData(iBean IBean) IBean {
   if err := json.Unmarshal([]byte(r.Data), &iBean); err != nil {
      return nil
   }
   return iBean
}

func TestJson(t *testing.T) {
   tickersJsonBytes := []byte(`{"code": 0, "message": "success", "data": { "tickers": [ { "_id": "5a33741cce79d2cf9bf5942c", "display_pair_name": "EOS/KRW", "price": 12.5284441, "volume": 202401841.79944953 }]}}`)
   var result Result
   if err := json.Unmarshal(tickersJsonBytes, &result); err != nil {
      t.Fatal(err)
   }
   var tickersResult TickersResult
   t.Log(result.ParseData(&tickersResult))

   studentJsonBytes := []byte(`{"code":0,"message":"success","data":{"name":"5a33741cce79d2cf9bf5942c","class":"A109","weight":12.5284441,"age":20}}`)
   var studentResult Result
   if err := json.Unmarshal(studentJsonBytes, &studentResult); err != nil {
      t.Fatal(err)
   }
   var student Student
   t.Log(studentResult.ParseData(&student))
}