Fixing setuptools "TypeError: swig_sources()" error

I was trying to update to a newer version of Jinja2 on osx to meet Zine dependencies and I got the following error:

Traceback (most recent call last):
[…snip…]
  File "/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/setuptools/command/build_ext.py", line 77, in swig_sources
    sources = _build_ext.swig_sources(self, sources) or sources
TypeError: swig_sources() takes exactly 3 arguments (2 given)

From the traceback it became clear that I was using an old version of setuptools.

Running:

$ locate /bin/easy_install
/usr/bin/easy_install
/usr/bin/easy_install-2.5
/usr/local/bin/easy_install
/usr/local/bin/easy_install-2.5

Showed I should be using /usr/local/bin/easy_install; so:
sudo mv /usr/bin/easy_install /usr/bin/easy_install.old

Resolved the problem.