--- a/core_marking1/collatz_test1.scala	Sun Sep 15 12:57:59 2024 +0100
+++ b/core_marking1/collatz_test1.scala	Mon Jul 21 16:38:07 2025 +0100
@@ -1,8 +1,11 @@
 
+def urbanmain() = {
+  import C1._
 
-assert(C1.collatz(1) == 0)
-assert(C1.collatz(6) == 8)
-assert(C1.collatz(9) == 19)
-assert(C1.collatz(9000) == 47)
+  assert(C1.collatz(1) == 0)
+  assert(C1.collatz(6) == 8)
+  assert(C1.collatz(9) == 19)
+  assert(C1.collatz(9000) == 47)
 
+}