QApplication.exec_() is designed around C++: it's convenient to have exec_()
return a value instead of calling exit() because it makes additional cleanup
much easier.

But in Python, sys.exit() only raises an exception, which can be intercepted if
needed. So there is no reason not to automatically raise an exception. In order
to both fix the ugly exec_() and maintain compatibility with programs that
don't expect exec_() to raise an exception, I propose to simply define

def execute(self):
    sys.exit(self.exec_())

or, perhaps it would be wiser to define:

def execute(self):
    code = self.exec_()
    if code!=0:
        sys.exit(code)

so that execution does not stop if exec_() is successful.


Likewise, I don't think there is any reason for QApplication to demand passing
sys.argv: unlike in C++, it doesn't have to be manually passed, so
QApplication() could be QApplication(sys.argv).


So the typical program prologue would change from

if __name__=="__main__":
    import sys
    app = QApplication(sys.argv)
    ...
    sys.exit(app.exec_())

to

if __name__=="__main__":
    app = QApplication()
    ...
    app.execute()


The icing on the cake would be to use the with statement:

if __name__=="__main__":
    with QApplication():
      ...

where QApplication's __exit__ would simply be execute().