diff -r ec9773fe1dc0 -r ef5f62bf5987 testing2/docdiff_test4.scala
--- a/testing2/docdiff_test4.scala	Tue Oct 29 14:34:51 2019 +0000
+++ b/testing2/docdiff_test4.scala	Tue Oct 29 23:56:13 2019 +0000
@@ -1,4 +1,5 @@
 
+import CW7a._
 
 val urban_list1 = List("a", "b", "b", "c", "d")
 val urban_list2 = List("d", "b", "d", "b", "d")