The error on 3.2 comes from the lru_cache, here's a minimal testcase to reproduce it:
>>> from functools import lru_cache
>>> @lru_cache()
... def func(arg): raise ValueError()
... 
>>> func(3)
Traceback (most recent call last):
  File "/home/wolf/dev/py/3.2/Lib/functools.py", line 176, in wrapper
    result = cache[key]
KeyError: (3,)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/wolf/dev/py/3.2/Lib/functools.py", line 180, in wrapper
    result = user_function(*args, **kwds)
  File "<stdin>", line 2, in func
ValueError


Raymond, is this expected or should I open another issue?