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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 stop(self):
 """ Stop this Tracer. """

        if hasattr(sys, "gettrace") and self.log:
            if sys.gettrace() != self._trace:
                msg = "Trace function changed, measurement is likely wrong: %r"
                print >> sys.stdout, msg % sys.gettrace()
        sys.settrace(None)