--- a/marking2/danube_test5.scala	Tue Oct 29 23:56:13 2019 +0000
+++ b/marking2/danube_test5.scala	Wed Oct 30 11:28:44 2019 +0000
@@ -1,9 +1,10 @@
 
 // first test 
 
+import CW7b._
 
 def urban_groupById(ratings: List[(String, String)]) = 
-  ratings.groupBy(_._1).mapValues(_.map(_._2)) 
+  ratings.groupBy(_._1).view.mapValues(_.map(_._2)).toMap 
 
 def urban_get_csv_file(name: String) : List[String] = {
   import io.Source