title: PyQt: connecting slots with custom objects via Qt Designer
body: <p>I have a PyQt widget that sends signals with <code>numpy.ndarray</code> data. And I have another PyQt widget that has a slot with <code>numpy.ndarray</code> data.</p>
  
  <p>Both widget are located on my main window, that is compiled from *.ui file. The widgets are set as promoted widgets.</p>
  
  <p>Cannot I somehow connect the signal and slot in Qt Creator?</p>
  
  <p>Just now it gives me the next error:</p>
  
  <pre><code>TypeError: C++ type 'ndarray' is not supported as a slot argument type
  </code></pre>