text: // This is INCORRECT
  const { series, parallel } = require('gulp');
  
  const clean = function(cb) {
    // body omitted
    cb();
  };
  
  const css = series(clean, function(cb) {
    // body omitted
    cb();
  });
  
  const javascript = series(clean, function(cb) {
    // body omitted
    cb();
  });
  
  exports.build = parallel(css, javascript);