Migrate From PyQt3 to PyQt4

[nusch]

I want to migrate from qt,pyqt,pykde 3 to 4 and remove all *.py files
to work with newer version, also after remove pyqt3support. How can I
do it in easy way ? I've read here http://www.mail-archive.com/pyqt@riverbankcomputing.com/msg15009.html
something about deprecation warning but can't see such warning
anywhere. My python modules also produce a lot of output so I can
easily overlook such information. Is there a way to stop execution
after every old qt3 class/method? I know I can remove all qt3,
qt3support libs, but I don't want to make whole system unstable
because of one project.