def close_application(self):
    choice = QtGui.QMessageBox.question(self, 'Warning', 'Do you want to quit?', (QtGui.QMessageBox.Yes | QtGui.QMessageBox.No))
    if (choice == QtGui.QMessageBox.Yes):
        self.action_cb['on_close']()
    else:
        pass
def close_application(self):
    choice = QtGui.QMessageBox.question(self, 'Warning', 'Do you want to quit?', (QtGui.QMessageBox.Yes | QtGui.QMessageBox.No))
    if (choice == QtGui.QMessageBox.Yes):
        self.action_cb['on_close']()
    else:
        pass