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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def reactivate(self):
 """ Called when a sub-protocol is finished. This disconnects the sub-protocol and redraws the main menu UI. """

        self._protocol.connectionLost(None)
        self._protocol = None
        self.terminal.reset()
        self._window.filthy()
        self._window.repaint()