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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 fulfill(self, agreement_id, amount, receiver_address, sender_address, lock_condition_id, release_condition_id, account):
 """ Fulfill the escrow reward condition. :param agreement_id: id of the agreement, hex str :param amount: Amount of tokens, int :param receiver_address: ethereum address of the receiver, hex str :param sender_address: ethereum address of the sender, hex str :param lock_condition_id: id of the condition, str :param release_condition_id: id of the condition, str :param account: Account instance :return: """

        return self._fulfill(
            agreement_id,
            amount,
            receiver_address,
            sender_address,
            lock_condition_id,
            release_condition_id,
            transact={'from': account.address,
                      'passphrase': account.password}
        )