--- a/Collection.st	Sat May 07 12:30:11 2016 +0200
+++ b/Collection.st	Sat May 07 12:32:29 2016 +0200
@@ -3235,6 +3235,29 @@
     "
 !
 
+keysAndValuesDetectKey:aBlock ifNone:exceptionalValue
+    "for each key-value pair in the receiver, evaluate the argument, aBlock
+     and return the key/index for which aBlock returns true the very first time.
+     If none of the evaluations returns true, return the result of the
+     evaluation of the exceptionBlock"
+     
+    self keysAndValuesDo:[:key :value |
+        (aBlock value:key value:value) ifTrue:[^ key].
+    ].
+    ^ exceptionalValue value
+
+    "
+     |ages|
+
+     ages := Dictionary new.
+     ages at:'cg' put:37.
+     ages at:'ca' put:33.
+     ages at:'sv' put:36.
+     ages at:'tk' put:28.
+     ages keysAndValuesDetectKey:[:name :age | age = 33] ifNone:nil.
+    "
+!
+
 keysAndValuesDo:aTwoArgBlock
     "evaluate the argument, aBlock for every element in the collection,
      passing both index and element as arguments.