title: pyQt: query checkbox checked in a QListWidget
body: <p>I am adding Checkboxes to a QlistWidget like this</p>
  
  <pre><code>item = QtGui.QListWidgetItem(listWidget)
  ch = QtGui.QCheckBox()
  listWidget.setItemWidget(item, ch)
  </code></pre>
  
  <p>like here
  <a href="https://stackoverflow.com/questions/4510341/cant-change-state-of-checkable-qlistviewitem-with-custom-widget">Can&#39;t change state of checkable QListViewItem with custom widget</a></p>
  
  <p>but i am somehow unable to get the checkbox item back at the time i want to know if they are checked by the user. I must be missing something very basic...</p>
  
  <pre><code>for index in xrange(listWidget.count()): 
      it=listWidget.itemAt(index,0)
  </code></pre>
  
  <p>So i need to know which checkboxes in the list the user checked?
  I cant figure what to do with the returned list item object to get the checkbox state.
  Should i use checkbox callbacks instead? Seems easier</p>