--- a/KeyedCollection.st	Thu Apr 27 14:14:45 2017 +0200
+++ b/KeyedCollection.st	Fri Apr 28 14:39:45 2017 +0200
@@ -429,6 +429,15 @@
 
 !KeyedCollection methodsFor:'removing'!
 
+removeAllKeys:aCollection
+    "remove all keys of the argument, aCollection from the receiver.
+     Raises an error, if some element-to-remove is not in the receiver."
+
+    aCollection do:[:element | self removeKey:element].
+
+    "Modified (comment): / 28-04-2017 / 13:36:15 / stefan"
+!
+
 removeKey:aKey
     "remove key (and the value stored under that key) from the
      receiver; raise an error if no such element is contained"