OrderedDict data structure in bzrlib?

[Kirill Müller]

Hello,

I am planning to add a histedit command to the rewrite plugin [1], and a 
data structure like collections.OrderedDict [2] would help a lot. 
Unfortunately, OrderedDict is new in Python 2.7. Is there a similar data 
structure, compatible with all supported versions of Python, already 
available in bzrlib?

I'd appreciate any feedback.


Best regards,

Kirill


[1] https://bugs.launchpad.net/bzr-rewrite/+bug/243150
[2] http://docs.python.org/library/collections.html#collections.OrderedDict