Deprecate two methods (which I seriously doubt anyone ever used, but they were documented so...) because they cannot be implemented efficiently on top of collections.SortedDict in Python 2.7 and up.

django/utils/datastructures.py

@@ -1,6 +1,8 @@
 import copy
+import warning
 from types import GeneratorType
 
+
 class MergeDict(object):
     """
     A simple class for creating new "virtual" dictionaries that actually look
@@ -191,10 +193,17 @@ class SortedDict(dict):
 
     def value_for_index(self, index):
         """Returns the value of the item at the given zero-based index."""
+        # This, and insert() are deprecated because they cannot be implemented
+        # using collections.OrderedDict (Python 2.7 and up), which we'll
+        # eventually switch to
+        warning.warn(PendingDeprecationWarning,
+            "SortedDict.value_for_index is deprecated", stacklevel=2)
         return self[self.keyOrder[index]]
 
     def insert(self, index, key, value):
         """Inserts the key, value pair before the item with the given index."""
+        warning.warn(PendingDeprecationWarning,
+            "SortedDict.insert is deprecated", stacklevel=2)
         if key in self.keyOrder:
             n = self.keyOrder.index(key)
             del self.keyOrder[n]

docs/ref/utils.txt

@@ -112,10 +112,14 @@ to distinguish caches by the ``Accept-language`` header.
 
     .. method:: insert(index, key, value)
 
+        .. deprecated:: 1.5
+
         Inserts the key, value pair before the item with the given index.
 
     .. method:: value_for_index(index)
 
+        .. deprecated:: 1.5
+
         Returns the value of the item at the given zero-based index.
 
 Creating a new SortedDict