diff -r 7acbef680bef -r f5c0749858fd main_marking4/knight1_test4.scala
--- a/main_marking4/knight1_test4.scala	Sun Jan 15 10:58:13 2023 +0000
+++ b/main_marking4/knight1_test4.scala	Sat Mar 11 22:01:53 2023 +0000
@@ -3,5 +3,17 @@
 
 val f_urban = (x:(Int, Int)) => if (x._1 > 3) Some(List(x)) else None
 
+
+import scala.concurrent._
+import scala.concurrent.duration._
+import ExecutionContext.Implicits.global
+import scala.language.postfixOps 
+
+lazy val f = Future {
+
 assert(first(List((1,0),(2,0),(3,0),(4,0)), f_urban) == Some(List((4,0))))
 assert(first(List((1,0),(2,0),(3,0)), f_urban) == None)
+}
+
+Await.result(f, 32 second)
+