I'm still not entirely happy about this, particularly because it's in IPython.external - these are third party modules that we ship - in this case, the [decorator package](https://pypi.python.org/pypi/decorator). We try to only change them from upstream when absolutely necessary. Can you try to work the fix in [upstream](http://code.google.com/p/micheles/source/browse/#hg%2Fdecorator)?