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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 set_state_from_file(self, filename):
 """Sets the state of the sampler back to the instance saved in a file. """

        with self.io(filename, 'r') as fp:
            rstate = fp.read_random_state()
        # set the numpy random state
        numpy.random.set_state(rstate)
        # set emcee's generator to the same state
        self._sampler.random_state = rstate