Python OrderedDict 按日期排序

我正在尝试使用 OrderedDict (Raymond Hettingersversion http://code.activestate.com/recipes/576693/对于 pre2.7 Python），其中我的键是日期。但是它没有正确排序，我想它可能是根据 ID 排序的。

有人对如何做到这一点有任何建议吗？

In [1]: from collections import OrderedDict

In [2]: import operator

In [3]: from datetime import date

In [4]: d = {date(2012, 1, 1): 123, date(2010,2,5): 542, date(2011,3,3):76 }

In [5]: d # Good old dict
Out[5]: #it seems sorted, but it isn't guaranteed to be that way.
{datetime.date(2010, 2, 5): 542,
 datetime.date(2011, 3, 3): 76,
 datetime.date(2012, 1, 1): 123}

In [6]: o = OrderedDict(sorted(d.items(), key=operator.itemgetter(0)))

In [7]: o #Now it is ordered(and sorted, because we give it by sorted order.).
Out[7]: OrderedDict([(datetime.date(2010, 2, 5), 542), (datetime.date(2011, 3, 3), 76), (datetime.date(2012, 1, 1), 123)])