how to implement QApplication.notify()

I am getting this error:

Qt has caught an exception thrown from an event handler. Throwing
exceptions from an event handler is not supported in Qt. You must
reimplement QApplication::notify() and catch all exceptions there.

terminate called after throwing an instance of 'std::bad_alloc'
what(): St9bad_alloc

So I put:

def notify(self, receiver, event):

I want to see what function is throwing the exception and what the exception is. What do I have to put in the notify function to do this?

I am using Python but help in C++ would be welcome too.