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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 redo(self):
 """Redo the next metadata change. Returns ------- up : UpdateInfo instance """

        args = self._undo_stack.forward()
        if args is None:
            return
        clusters, field, value, up, undo_state = args
        self.set(field, clusters, value, add_to_stack=False)

        # Return the UpdateInfo instance of the redo action.
        up.history = 'redo'

        self.emit('cluster', up)
        return up