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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 get_mol_filename(self):
        '''Returns mol filename'''
        mol_filename = parsers.get_mol_filename(self.__chebi_id)

        if mol_filename is None:
            mol_filename = parsers.get_mol_filename(self.get_parent_id())

        if mol_filename is None:
            for parent_or_child_id in self.__get_all_ids():
                mol_filename = \
                    parsers.get_mol_filename(parent_or_child_id)

                if mol_filename is not None:
                    break

        return mol_filename