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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 propagate(self, assumptions=[], phase_saving=0):
 """ Propagate a given set of assumption literals. """


        if self.maplesat:
            if self.use_timer:
                 start_time = time.clock()

            # saving default SIGINT handler
            def_sigint_handler = signal.signal(signal.SIGINT, signal.SIG_DFL)

            st, props = pysolvers.maplechrono_propagate(self.maplesat, assumptions, phase_saving)

            # recovering default SIGINT handler
            def_sigint_handler = signal.signal(signal.SIGINT, def_sigint_handler)

            if self.use_timer:
                self.call_time = time.clock() - start_time
                self.accu_time += self.call_time

            return bool(st), props if props != None else []