[PyQt] Assign Label Text as number in Hz

[Alfalfa]

I forgot that python2 need arguments to init super. Simply replace it with:
super(ClassName, self).__init__()

so for the example above:
super(WorkerThread, self).__init__()
super(Main, self).__init__()

I don't know what it does exactly but it is mandatory. Btw, as you are developping a new app, maybe you should consider going for the lastest versions, as PyQt4 is quite old. You'll less likely need to port your code again in the future. If you need help to get started I've posted several examples for PyQt5 on gitlab: https://gitlab.com/users/william.belanger/snippets