def unsubscribe(self):
        """Unsubscribe self.handlers from signals."""
        for signum, handler in self._previous_handlers.items():
            signame = self.signals[signum]
            
            if handler is None:
                self.bus.log("Restoring %s handler to SIG_DFL." % signame)
                handler = _signal.SIG_DFL
            else:
                self.bus.log("Restoring %s handler %r." % (signame, handler))
            
            try:
                our_handler = _signal.signal(signum, handler)
                if our_handler is None:
                    self.bus.log("Restored old %s handler %r, but our "
                                 "handler was not registered." %
                                 (signame, handler), level=30)
            except __HOLE__:
                self.bus.log("Unable to restore %s handler %r." %
                             (signame, handler), level=40, traceback=True)
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/cherrypy/cherrypy/process/plugins.py/SignalHandler.unsubscribe