title: how to get the index of the QListWidgetItem in the itemDoubleClicked
body: <p>i have connected a function to a QListWidget's itemDoubleClicked. as far as i know it passes two arguments to the function (self, item). i want to get the index of this item so that i can access an item from another list which has the same indexes. </p>
  
  <pre><code>self.ResultList.itemDoubleClicked.connect(self.switch_image)
  </code></pre>
  
  <p>the function </p>
  
  <pre><code>def switch_image(self, item):
      #temp = QtWidgets.QListWidgetItem
      #t = temp.text()
  
      ''' what should be here '''
  
      # ind = item.index
      print(t)
  </code></pre>