--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/marking1/drumb_test4.scala	Sat Feb 02 01:21:43 2019 +0000
@@ -0,0 +1,6 @@
+
+
+assert(get_delta(None, None) == None)
+assert(get_delta(Some(100.0), None) == None)
+assert(get_delta(None, Some(50.0)) == None)
+assert(get_delta(Some(100.0), Some(50.0)) == Some(1.0))