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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_agreement(self, agreement_id):
 """ Retrieve the agreement for a agreement_id. :param agreement_id: id of the agreement, hex str :return: the agreement attributes. """

        agreement = self.contract_concise.getAgreement(agreement_id)
        if agreement and len(agreement) == 6:
            agreement = AgreementValues(*agreement)
            did = add_0x_prefix(agreement.did.hex())
            cond_ids = [add_0x_prefix(_id.hex()) for _id in agreement.condition_ids]

            return AgreementValues(
                did,
                agreement.owner,
                agreement.template_id,
                cond_ids,
                agreement.updated_by,
                agreement.block_number_updated
            )

        return None