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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_next_change(self):
 """ Redo the last undone change in the TransformedStructure. Raises: IndexError: If already at the latest change. """

        if len(self._undone) == 0:
            raise IndexError("Can't redo. Already at latest change.")
        h, s = self._undone.pop()
        self.history.append(h)
        self.final_structure = s