Method is overloaded to accept either a list of transformed structures
        or transmuter, it which case it appends the second transmuter"s
        structures.

        Args:
            tstructs_or_transmuter: A list of transformed structures or a
                transmuter.

def append_transformed_structures(self, tstructs_or_transmuter):
        """
        Method is overloaded to accept either a list of transformed structures
        or transmuter, it which case it appends the second transmuter"s
        structures.

        Args:
            tstructs_or_transmuter: A list of transformed structures or a
                transmuter.
        """
        if isinstance(tstructs_or_transmuter, self.__class__):
            self.transformed_structures.extend(tstructs_or_transmuter
                                               .transformed_structures)
        else:
            for ts in tstructs_or_transmuter:
                assert isinstance(ts, TransformedStructure)
            self.transformed_structures.extend(tstructs_or_transmuter)