diff -r 244df77507c2 -r 253d1ccb65de core_marking2/docdiff_test2.scala
--- a/core_marking2/docdiff_test2.scala	Sun Sep 15 12:57:59 2024 +0100
+++ b/core_marking2/docdiff_test2.scala	Mon Jul 21 16:38:07 2025 +0100
@@ -1,10 +1,12 @@
 
-import C2._
+def urbanmain() = {
+  import C2._
 
-assert(occurrences(List("a", "b", "b", "c", "d")) == Map("a" -> 1, "b" -> 2, "c" -> 1, "d" -> 1))
+  assert(occurrences(List("a", "b", "b", "c", "d")) == Map("a" -> 1, "b" -> 2, "c" -> 1, "d" -> 1))
 
-assert(occurrences(List("d", "b", "d", "b", "d")) == Map("d" -> 3, "b" -> 2))
+  assert(occurrences(List("d", "b", "d", "b", "d")) == Map("d" -> 3, "b" -> 2))
 
-assert(occurrences(List("b", "b", "b", "b", "b")) == Map("b" -> 5))
+  assert(occurrences(List("b", "b", "b", "b", "b")) == Map("b" -> 5))
 
-assert(occurrences(Nil) == Map())
+  assert(occurrences(Nil) == Map())
+}