--- a/ProtoObject.st	Wed Mar 21 12:22:57 2018 +0100
+++ b/ProtoObject.st	Thu Mar 22 11:44:25 2018 +0100
@@ -790,12 +790,9 @@
 !
 
 ifNotNil:aBlockOrValue
-    (aBlockOrValue isBlockWithArgumentCount:1) ifTrue:[
-        ^ aBlockOrValue value:self.
-    ].
-    ^ aBlockOrValue value
+    ^ aBlockOrValue valueWithOptionalArgument:self
 
-    "Modified: / 18-03-2017 / 18:27:49 / stefan"
+    "Modified: / 22-03-2018 / 11:39:11 / stefan"
 !
 
 isBehavior