How to use the @tradle/constants.OP_RETURN_PREFIX function in @tradle/constants

var createTxDB = require('./txDB')
var Errors = require('./errors')
var utils = require('./utils')
var RETRY_UNCHAIN_ERRORS = [
  ChainLoader.Errors.ParticipantsNotFound,
  ChainLoader.Errors.FileNotFound
].map(function (ErrType) {
  return ErrType.type
})

var TYPE = constants.TYPE
var SIGNEE = constants.SIGNEE
var ROOT_HASH = constants.ROOT_HASH
var PREV_HASH = constants.PREV_HASH
var CUR_HASH = constants.CUR_HASH
var PREFIX = constants.OP_RETURN_PREFIX
var NONCE = constants.NONCE
var CONFIRMATIONS_BEFORE_CONFIRMED = 10
var KEY_PURPOSE = 'messaging'
Driver.MIN_BALANCE = 10000
Driver.CHAIN_WRITE_THROTTLE = 60000
Driver.CHAIN_READ_THROTTLE = 60000
Driver.SEND_THROTTLE = 10000
Driver.CATCH_UP_INTERVAL = 2000
Driver.Zlorp = Zlorp
Driver.Kiki = kiki
Driver.Identity = Identity
Driver.Wallet = Wallet
Driver.Messengers = Messengers
Driver.EventType = EventType
// TODO: export other deps

var Dir = require('./dir');
var createIdentityDB = require('./identityDB');
var createMsgDB = require('./msgDB');
var createTxDB = require('./txDB');
var Errors = require('./errors');
var utils = require('./utils');
var RETRY_UNCHAIN_ERRORS = [ChainLoader.Errors.ParticipantsNotFound, ChainLoader.Errors.FileNotFound].map(function (ErrType) {
  return ErrType.type;
});

var TYPE = constants.TYPE;
var SIGNEE = constants.SIGNEE;
var ROOT_HASH = constants.ROOT_HASH;
var PREV_HASH = constants.PREV_HASH;
var CUR_HASH = constants.CUR_HASH;
var PREFIX = constants.OP_RETURN_PREFIX;
var NONCE = constants.NONCE;
var CONFIRMATIONS_BEFORE_CONFIRMED = 10;
var KEY_PURPOSE = 'messaging';
Driver.MIN_BALANCE = 10000;
Driver.CHAIN_WRITE_THROTTLE = 60000;
Driver.CHAIN_READ_THROTTLE = 60000;
Driver.SEND_THROTTLE = 10000;
Driver.CATCH_UP_INTERVAL = 2000;
Driver.Zlorp = Zlorp;
Driver.Kiki = kiki;
Driver.Identity = Identity;
Driver.Wallet = Wallet;
Driver.Messengers = Messengers;
Driver.EventType = EventType;
// TODO: export other deps