我有一个gulp文件，该文件与gulp 4的最新更新有问题，我收到Assert错误（AssertionError [ERR_ASSERTION]：必须指定任务功能），它似乎（从谷歌搜索）与如何定义任务有关，但不确定是否是这种情况，以及需要更改什么。节点：节点-v v14.16.0
CLI版本：2.3.0本地版本：4.0.2
NPM：6.14.11以下是代码

// ### CSS processing pipeline
// Example
// ```
// gulp.src(cssFiles)
//   .pipe(cssTasks('main.css')
//   .pipe(gulp.dest(path.dist + 'styles'))
// ```
var cssTasks = function(filename) {
  return lazypipe()
    .pipe(function() {
      return gulpif(!enabled.failStyleTask, plumber());
    })
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.init());
    })
    .pipe(function() {
      return gulpif('*.less', less());
    })
    .pipe(function() {
      return gulpif('*.scss', sass({
        outputStyle: 'nested', // libsass doesn't support expanded yet
        precision: 10,
        includePaths: ['.'],
        errLogToConsole: !enabled.failStyleTask
      }));
    })
    .pipe(concat, filename)
    .pipe(autoprefixer, {
      browsers: [
        'last 2 versions',
        'android 4',
        'opera 12'
      ]
    })
    .pipe(cssNano, {
      safe: true
    })
    .pipe(function() {
      return gulpif(enabled.rev, rev());
    })
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.write('.', {
        sourceRoot: 'assets/styles/'
      }));
    })();
};

// ### JS processing pipeline
// Example
// ```
// gulp.src(jsFiles)
//   .pipe(jsTasks('main.js')
//   .pipe(gulp.dest(path.dist + 'scripts'))
// ```
var jsTasks = function(filename) {
  return lazypipe()
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.init());
    })
    .pipe(concat, filename)
    .pipe(uglify, {
      compress: {
        'drop_debugger': enabled.stripJSDebug
      }
    })
    .pipe(function() {
      return gulpif(enabled.rev, rev());
    })
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.write('.', {
        sourceRoot: 'assets/scripts/'
      }));
    })();
};

// ### Write to rev manifest
// If there are any revved files then write them to the rev manifest.
// See https://github.com/sindresorhus/gulp-rev
var writeToManifest = function(directory) {
  return lazypipe()
    .pipe(gulp.dest, path.dist + directory)
    .pipe(browserSync.stream, {match: '**/*.{js,css}'})
    .pipe(rev.manifest, revManifest, {
      base: path.dist,
      merge: true
    })
    .pipe(gulp.dest, path.dist)();
};

// ## Gulp tasks
// Run `gulp -T` for a task summary

// ### Styles
// `gulp styles` - Compiles, combines, and optimizes Bower CSS and project CSS.
// By default this task will only log a warning if a precompiler error is
// raised. If the `--production` flag is set: this task will fail outright.
gulp.task('styles', ['wiredep'], function() {
  var merged = merge();
  manifest.forEachDependency('css', function(dep) {
    var cssTasksInstance = cssTasks(dep.name);
    if (!enabled.failStyleTask) {
      cssTasksInstance.on('error', function(err) {
        console.error(err.message);
        this.emit('end');
      });
    }
    merged.add(gulp.src(dep.globs, {base: 'styles'})
      .pipe(plumber({errorHandler: onError}))
      .pipe(cssTasksInstance));
  });
  return merged
    .pipe(writeToManifest('styles'));
});

// ### Scripts
// `gulp scripts` - Runs JSHint then compiles, combines, and optimizes Bower JS
// and project JS.
gulp.task('scripts', function() {
  var merged = merge();
  manifest.forEachDependency('js', function(dep) {
    merged.add(
      gulp.src(dep.globs, {base: 'scripts'})
        .pipe(plumber({errorHandler: onError}))
        .pipe(jsTasks(dep.name))
    );
  });
  return merged
    .pipe(writeToManifest('scripts'));
});

// ### Fonts
// `gulp fonts` - Grabs all the fonts and outputs them in a flattened directory
// structure. See: https://github.com/armed/gulp-flatten
gulp.task('fonts', function() {
  return gulp.src(globs.fonts)
    //.pipe(flatten())
    .pipe(gulp.dest(path.dist + 'fonts'))
    .pipe(browserSync.stream());
});

// ### Images
// `gulp images` - Run lossless compression on all the images.
gulp.task('images', function() {
  return gulp.src(globs.images)
    .pipe(imagemin([
      imagemin.jpegtran({progressive: true}),
      imagemin.gifsicle({interlaced: true}),
      imagemin.svgo({plugins: [
        {removeUnknownsAndDefaults: false},
        {cleanupIDs: false}
      ]})
    ]))
    .pipe(gulp.dest(path.dist + 'images'))
    .pipe(browserSync.stream());
});

// ### JSHint
// `gulp jshint` - Lints configuration JSON and project JS.
gulp.task('jshint', function() {
  return gulp.src([
    'bower.json', 'gulpfile.js'
  ].concat(project.js))
    .pipe(jshint())
    .pipe(jshint.reporter('jshint-stylish'))
    .pipe(gulpif(enabled.failJSHint, jshint.reporter('fail')));
});

// ### Clean
// `gulp clean` - Deletes the build folder entirely.
gulp.task('clean', require('del').bind(null, [path.dist]));

// ### Watch
// `gulp watch` - Use BrowserSync to proxy your dev server and synchronize code
// changes across devices. Specify the hostname of your dev server at
// `manifest.config.devUrl`. When a modification is made to an asset, run the
// build step for that asset and inject the changes into the page.
// See: http://www.browsersync.io
gulp.task('watch', function() {
  browserSync.init({
    files: ['{lib,templates}/**/*.php', '*.php'],
    proxy: config.devUrl,
    snippetOptions: {
      whitelist: ['/wp-admin/admin-ajax.php'],
      blacklist: ['/wp-admin/**']
    }
  });
  gulp.watch([path.source + 'styles/**/*'], ['styles']);
  gulp.watch([path.source + 'scripts/**/*'], ['scripts']);
  gulp.watch([path.source + 'fonts/**/*'], ['fonts']);
  gulp.watch([path.source + 'images/**/*'], ['images']);
  gulp.watch(['bower.json', 'assets/manifest.json'], ['build']);
});

// ### Build
// `gulp build` - Run all the build tasks but don't clean up beforehand.
// Generally you should be running `gulp` instead of `gulp build`.
gulp.task('build', function(callback) {
  runSequence('styles',
              'scripts',
              ['fonts', 'images'],
              callback);
});

// ### Wiredep
// `gulp wiredep` - Automatically inject Less and Sass Bower dependencies. See
// https://github.com/taptapship/wiredep
gulp.task('wiredep', function() {
  var wiredep = require('wiredep').stream;
  return gulp.src(project.css)
    .pipe(wiredep())
    .pipe(changed(path.source + 'styles', {
      hasChanged: changed.compareSha1Digest
    }))
    .pipe(gulp.dest(path.source + 'styles'));
});

任何帮助都是非常感谢的。