title: "Task function must be specified at Gulp.set" error when running gulp
body: <p>I always have the same error when installing gulp:</p>
  
  <pre><code>C:\Users\Thomas\Desktop\Sites CT Graphics\colpaertmarc.be&gt;gulp
  assert.js:350
  throw err;
  ^
  </code></pre>
  
  <blockquote>
    <p>AssertionError [ERR_ASSERTION]: Task function must be specified
        at Gulp.set [as _setTask] (C:\Users\Thomas\Desktop\Sites CT Graphics\colpaertmarc.be\node_modules\undertaker\lib\set-task.js:10:3)
        at Gulp.task (C:\Users\Thomas\Desktop\Sites CT Graphics\colpaertmarc.be\node_modules\undertaker\lib\task.js:13:8)
        at Object. (C:\Users\Thomas\Desktop\Sites CT Graphics\colpaertmarc.be\gulpfile.js:19:6)
        at Module._compile (internal/modules/cjs/loader.js:689:30)
        at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
        at Module.load (internal/modules/cjs/loader.js:599:32)
        at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
        at Function.Module._load (internal/modules/cjs/loader.js:530:3)
        at Module.require (internal/modules/cjs/loader.js:637:17)
        at require (internal/modules/cjs/helpers.js:22:18)</p>
  </blockquote>