title: Setting default value for QcomboBox as empty
body: <p>I'm on python 2.7 using pyqt 4.10, I've created a QcomboBox </p>
  
  <pre><code>for items in item_all:
      self.comboBox.addItem(items)
  </code></pre>
  
  <p>the <code>item_all</code> list is working perfectly  but I need it to start with the default value as Empty (note that <code>item_all</code> list is being called from a DB table so I can't have an empty value to use it) </p>