 
 
 
-    private mutating func put(_ keySet: KeySet, _ value: Value)
+    private mutating func put(keySet: KeySet, value: Value)
     {
         assert(keySet.count == self.keys)
 
         // assign don't-care keys
-        var assignedKeys = keySet // FIXME: how to handle generating new key of KeyType? keySet.map({$0 ?? self.dontCareKey()})
+        let assignedKeys = keySet // FIXME: how to handle generating new key of KeyType? keySet.map({$0 ?? self.dontCareKey()})
 
         if !self.contains(assignedKeys)
         {

 *  Copyright 2016 Philip Erickson
 **************************************************************************************************/

// Adapted from the "Ternary Search Trie" as discussed in: Sedgewick, R., Wayne, K. (2011). 
// Algorithms, 4th Edition. Addison-Wesley. ISBN: 978-0-321-57351-3 

public struct MultikeyDictionary<KeyType: Comparable, Value>

 *  This file defines a multi-key dictionary data structure. 
 *
 *  Author: Philip Erickson
 *  Creation Date: 21 Dec 2016
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 *  in compliance with the License. You may obtain a copy of the License at
