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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 init_signal(self):

 """allow clean shutdown on sigint"""

        signal.signal(signal.SIGINT, lambda sig, frame: self.exit(-2))
        # need a timer, so that QApplication doesn't block until a real
        # Qt event fires (can require mouse movement)
        # timer trick from http://stackoverflow.com/q/4938723/938949
        timer = QtCore.QTimer()
        # Let the interpreter run each 200 ms:
        timer.timeout.connect(lambda: None)
        timer.start(200)
        # hold onto ref, so the timer doesn't get cleaned up
        self._sigint_timer = timer