@@ -42,11 +42,11 @@
 /**
  * \brief Removes the object for the specified key from the dictionary.
  *
  * \param key The key whose object should be removed
  */
-- (void)removeObjectForKey: (id)key;
+- (void)removeObjectForKey: (id <OFCopying>)key;
 
 #ifdef OF_HAVE_BLOCKS
 /**
  * \brief Replaces each object with the object returned by the block.
  *