title: PyCharm fails to debug Qt5 (PySide2) code - Error 'Shiboken.ObjectType' object is not iterable
body: <p>I have some experience with Python console applications and now trying to start with Qt for Python (Qt 5.12, PySide2). Actually I'm trying some basic tutorials to understand how it should work.</p>
  
  <p>So, I created very simple <strong>view.qml</strong>:</p>
  
  <pre><code>import QtQuick 2.0
  import QtQuick.Controls 2.13
  
  ApplicationWindow {
      visible: true
  
      Button {
          id: button
          text: qsTr("ClickOnMe")
      }
  
      Connections {
          target: button
          onClicked: con.say_hello()
      }
  }
  </code></pre>
  
  <p>and have following python code to work with it:</p>
  
  <pre><code>from PySide2.QtCore import QObject, Slot
  from PySide2.QtGui import QGuiApplication
  from PySide2.QtQml import QQmlApplicationEngine
  
  class Bridge(QObject):
      @Slot()
      def say_hello(context):
          print("Button clicked, Hello!", context)
  
  app = QGuiApplication([])
  engine = QQmlApplicationEngine()
  bridge = Bridge()
  
  context = engine.rootContext()
  context.setContextProperty("con", bridge)
  engine.load("view.qml")
  
  engine.rootObjects()
  exit(app.exec_())
  </code></pre>
  
  <p>It works fine when I simly run it - i.e. I see an application window with a button. I may click a button and see message printed in console.
  But when I try to debug it - it stops immediately on line <code>class Bridge(QObject):</code> with following exception:
  <code>&lt;class 'tuple'&gt;: (&lt;class 'TypeError'&gt;, TypeError("'Shiboken.ObjectType' object is not iterable"), &lt;traceback object at 0x7fe195b23680&gt;)</code></p>
  
  <p>I tryied the same in Qt Creator - works fine, not problems with Run and Debug (the minor issue - messages in Qt Creator console appear only after application termination). But I like PyCharm more so would like to understand how I may fix this problem and continue to use PyCharm with Qt.
  If it's important - I'm running ArchLinux.</p>