matplotlib/matplotlib — pull request #2142 by punchagan (2013-06-20 23:22:11+00:00)
Title: Try importing PySide, if we can't find sip.

If no QT_API is specified, we use the value in rcParams and the
default value for this is PyQt. If a user has PySide installed,
trying to use the qt backend fails, unless QT_API is specified or the
config file is modified. This commit, adds code to try and import
PySide, if an import of PyQt fails.