在Python 2.7.3中使用字典作为switch语句

>>> def f(a):
...      return {True: -a,a==0: 0,a > 0: a}[True]
... 
>>> f(-3)
3
>>> f(3)
3
>>> f(0)
0

键True用作else / default case,只有在没有其他键被评估为True时才返回.我猜这是假设迭代字典的某种评估顺序.

现在看一下最新版本的分支机构2.6,2.7,3.1和3.2的最新版本release announcement from the Python team：

Hash randomization causes the iteration order of dicts and sets to be
unpredictable and differ across Python runs. Python has never
guaranteed iteration order of keys in a dict or set,and applications
are advised to never rely on it. Historically,dict iteration order
has not changed very often across releases and has always remained
consistent between successive executions of Python. Thus,some
existing applications may be relying on dict or set ordering.

这是否意味着使用dicts作为切换呼叫将不再可能？或者也许我应该使用任何其他类(如OrderedDict或其他东西)？或者也许我完全不在了,它根本不应该影响到这一点？