ipython/ipython — pull request #2757 by juliantaylor (2013-01-07 22:19:53+00:00)
Title: check for complete pyside presence before trying to import

importing pyside partially and then falling back to pyqt causes a crash
in sip (see gh-1431)
To avoid it try to locate all modules before the import and should that
fail print a warning.

debian splits pyside into many small packages so sometimes people end up with incomplete pyside installations.