Redo the last undone change in the TransformedStructure.

        Raises:
            IndexError: If already at the latest change.

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