[PyQt] QCoreApplication::exec: The event loop is already running

[Brent Villalobos]

Brian Kelley wrote:
> When you start another mainwindow (or top level widget for that 
> matter) you don’t need to call exec_ or make another QApplication.

That's good. Along those same lines does Qt provide a way of querying 
whether a QApplication loop is already running so you can avoid making a 
new one?