A drop-in substitute for Py2.7's new collections.OrderedDict that works in Python 2.4-2.6.
Drop-in substitute for Py2.7's new collections.OrderedDict. The recipe has big-oh performance that matches regular dictionaries (amortized O(1) insertion/deletion/lookup and O(n) iteration/repr/copy/equality_testing).
Originally based on http://code.activestate.com/recipes/576693/