运行gulp 4.0.2报错

[itsocoo]

gulp版本号
CLI version: 2.3.0
Local version: 4.0.2

运行gulp命令
AssertionError [ERR_ASSERTION]: Task function must be specified
at Gulp.set [as _setTask] (/home/lighthouse/itsocoo/themes/hexo-theme-snippet/node_modules/under
taker/lib/set-task.js:10:3)
at Gulp.task (/home/lighthouse/itsocoo/themes/hexo-theme-snippet/node_modules/undertaker/lib/tas
k.js:13:8)
at /home/lighthouse/itsocoo/themes/hexo-theme-snippet/gulpfile.js:125:8
at Object. (/home/lighthouse/itsocoo/themes/hexo-theme-snippet/gulpfile.js:128:3)
at Module._compile (internal/modules/cjs/loader.js:1063:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
at Module.load (internal/modules/cjs/loader.js:928:32)
at Function.Module._load (internal/modules/cjs/loader.js:769:14)
at Module.require (internal/modules/cjs/loader.js:952:19)
at require (internal/modules/cjs/helpers.js:88:18) {
generatedMessage: false,
code: 'ERR_ASSERTION',
actual: false,
expected: true,
operator: '=='