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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 on_change(self, attr, old, new):
 """ Process change events adding timeout to process multiple concerted value change at once rather than firing off multiple plot updates. """

        self._queue.append((attr, old, new))
        if not self._active and self.plot.document:
            self.plot.document.add_timeout_callback(self.process_on_change, 50)
            self._active = True