ipython/ipython — pull request #4532 by takluyver (2013-11-13 20:51:34+00:00)
Title: Hide dynamically defined metaclass base from Sphinx.

The inheritance diagram extension in Sphinx 1.2 stores class references, which Sphinx then tries to pickle. This chokes on our dynamically defined base classes from the `with_metaclass` function. Starting the name with an underscore makes Sphinx ignore the class.

(Bug obscurity/fix simplicity) ratio is high.