deploy error

[xiawu]

I execute the command

truffle migrate --reset --network dev.fifs

then got the following error:

2_deploy_contracts.js
=====================
TypeError: namehash is not a function
    at getRootNodeFromTLD (/ens/migrations/2_deploy_contracts.js:20:15)
    at deployFIFSRegistrar (/ens/migrations/2_deploy_contracts.js:32:18)
    at module.exports (/ens/migrations/2_deploy_contracts.js:72:5)
    at Require.file (/usr/local/lib/node_modules/truffle/build/webpack:/packages/truffle-migrate/migration.js:59:1)
    at /usr/local/lib/node_modules/truffle/build/webpack:/packages/truffle-require/require.js:101:1
    at FSReqWrap.readFileAfterClose [as oncomplete] (internal/fs/read_file_context.js:53:3)
Truffle v5.0.1 (core: 5.0.1)
Node v10.16.0