--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/marking3/knight1_test4.scala	Sun Dec 09 01:36:49 2018 +0000
@@ -0,0 +1,5 @@
+
+val f = (x:(Int, Int)) => if (x._1 > 3) Some(List(x)) else None
+
+assert(CW7b.first(List((1,0),(2,0),(3,0),(4,0)), f) == Some(List((4,0))))
+assert(CW7b.first(List((1,0),(2,0),(3,0)), f) == None)