title: TypeError: QPixmap.toImage(): first argument of unbound method must have type 'QPixmap'
body: <p>I have a method that compare labels contents and return matches . The method is :</p>
  
  <pre><code>def get_selected_image(self):
      if self.labelDisplayBigImage.pixmap() is None:
          return False
      first_image = QtGui.QPixmap.toImage(self.labelDisplayBigImage.pixmap())
      selectable_images = [self.labelDisplayImage1, self.labelDisplayImage2, self.labelDisplayImage3,
                           self.labelDisplayImage4, self.labelDisplayImage5, self.labelDisplayImage6,
                           self.labelDisplayImage7, self.labelDisplayImage8]
  
      for i in range(len(selectable_images)):
          second_image = QtGui.QPixmap.toImage(selectable_images[i].pixmap())
          if first_image == second_image:
              return selectable_images[i].pixmap()
  </code></pre>
  
  <p>But got an error <code>TypeError: QPixmap.toImage(): first argument of unbound method must have type 'QPixmap'</code> . So what is the problem ?</p>