title: PyQt5 sending signals between classes?
body: <p>I have two couple classes(A, B, C, D), one of them is GUI class(A) which contains progressbar.
  So is it possible to send progress signals from B, C, D classes to A class ?</p>
  
  <p>in pseudo-code it's something like:</p>
  
  <pre><code>from a import A
  from PyQt5.Core import pyqtSignal
  
   class B(QObject):
       ...
       self.gui = A()
       progress = pyqtSignal(int)
  
       def connect_and_send(self, value):
           self.progress.connect(self.gui.progressBar)
           self.progress.emit(value)
  </code></pre>
  
  <p>But maybe there's something better, that my messy approach ?</p>