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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_asset_id(self, tx_id):
 """Return the tx_id of the first transaction. :param tx_id: Transaction id to start the recursive search. :return Transaction id parent. """

        tx = self.driver.instance.transactions.retrieve(txid=tx_id)
        assert tx is not None
        return tx['id'] if tx['operation'] == 'CREATE' else tx['asset']['id']