Index: django/utils/datastructures.py
===================================================================
--- django/utils/datastructures.py	(revision 5903)
+++ django/utils/datastructures.py	(working copy)
@@ -70,6 +70,14 @@
         for k in self.keyOrder:
             yield k
 
+    def __deepcopy__(self, memo):
+        from copy import deepcopy
+        dc = self.__class__()
+        for k, v in self.items():
+            dc[k] = deepcopy(v, memo)
+
+        return dc
+
     def items(self):
         return zip(self.keyOrder, self.values())