如何在swift中从firebase中删除子记录?

我想删除这个记录 firebase ,我不知道钥匙的名字。所以,我不知道怎么做。有人能帮我吗?

获取数组的代码如下

var databaseRefer : DatabaseReference!
  let userID = Auth.auth().currentUser?.uid
 databaseRefer = Database.database().reference(withPath: userID!)
 databaseRefer.observeSingleEvent(of: .value, with: { snapshot in
         if !snapshot.exists() { return }
          if snapshot.value is NSNull {
           print("not found")
            } else {
                for child in snapshot.children {
                let snap = child as! DataSnapshot

                   print(dict)

                   dict.forEach { item in

                       print(item.value)
               }
             }
       }
   })