Error(s), warning(s):

source_file.scala:7: warning: non-variable type argument String in type scala.collection.immutable.Map[String,Long] (the underlying of Map[String,Long]) is unchecked since it is eliminated by erasure
val output = data.map(x => if (x._2.isInstanceOf[Map[String, Long]]) (x._1 -> Some(x._2)) else x)
                                                ^
one warning found