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Solve the following problem using Python, implementing the functions described below, one line at a time
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<USER_TASK:>
Description:
 def _register_attribute(self, did, checksum, value, account, providers):
 """Register an DID attribute as an event on the block chain. :param did: 32 byte string/hex of the DID :param checksum: checksum of the ddo, hex str :param value: url for resolve the did, str :param account: account owner of this DID registration record :param providers: list of providers addresses """

        assert isinstance(providers, list), ''
        return self.send_transaction(
            'registerAttribute',
            (did,
             checksum,
             providers,
             value),
            transact={'from': account.address,
                      'passphrase': account.password}
        )