[Cython] Raising exceptions under python 2.5

[Greg Ewing]

Stefan Behnel wrote:

> it's actually faster to write
> 
>   raise KeyError, "No _ObserverItem found belonging to '%s'." % observer

But only if the exception is both raised and caught in
Pyrex or Cython code (because no exception instance is
created). Otherwise it makes little difference.

-- 
Greg