newstruct.json

{  
    "activities":[  
        {  
            "group_id":"87ehgiudnvijv",
            "aggregation": "actior",
            "sub_activities":[  
                {  
                    "id":5608536,
                    "stream_id":"d042d280-b566-11e5-8080-8001153bae6f",
                    "verb":"artist_tracking",
                    "category":"me",
                    "description":"Tracked",
                    "description_key":"tracked",
                    "timestamp":"2016-01-07T17:48:09+0000",
                    "like_count":0,
                    "is_liked":false,
                    "actor":{  
                        "user":{  
                            "id":21017358,
                            "first_name":"Xavier",
                            "last_name":"Cany",
                            "facebook_uid":"645131642",
                            "media_id":4348122,
                            "location":"San Diego, CA"
                        }
                    },
                    "object":{  
                        "artist":{  
                            "id":1647,
                            "name":"LCD Soundsystem",
                            "media_id":3697856,
                            "on_tour":false,
                            "tracker_count":310328
                        }
                    }
                }
            ]
        }
    ]
}