title: how to make qmenu item checkable pyqt4 python
body: <p>How can i make my qmenu checkable?</p>
  
  <pre><code>from PyQt4 import QtGui
  
  app = QtGui.QApplication([])
  
  menu = QtGui.QMenu()
  
  menu.addAction('50%')
  menu.addAction('100%')
  menu.addAction('200%')
  menu.addAction('400%')
  menu.show()
  
  app.exec_()
  </code></pre>