Как исправить ошибку events.js:154 при запуске gulp-autoprefixer?

const gulp         = require('gulp'),
      combine      = require('stream-combiner2').obj,
      gif          = require('gulp-if'),
      notify       = require('gulp-notify'),
      browserSync  = require('browser-sync').create(),
      sourcemaps   = require('gulp-sourcemaps'),
      stylus       = require('gulp-stylus'),
      autoprefixer = require('gulp-autoprefixer'),
      uncss        = require('gulp-uncss'),
      preprocess   = require('gulp-preprocess'),
      gih          = require('gulp-include-html'),
      htmlmin      = require('gulp-htmlmin'),
      del          = require('del'),
      replace      = require('gulp-replace'),
      sprite_png   = require('gulp.spritesmith'),
      sprite_svg   = require('gulp-svg-sprite'),
      imagemin     = require('gulp-imagemin'),
      pngquant     = require('imagemin-pngquant');


const isDevelopment = !process.env.NODE_ENV || process.env.NODE_ENV === 'development';



gulp.task('styles', function(){
   return combine(
      gulp.src("source/css/css.styl"),
      gif(isDevelopment, sourcemaps.init()),
      stylus(),
      autoprefixer(['last 2 versions'], {cascade : true}),
      gif(!isDevelopment, uncss({ html : ["public/*.html"] })),
      gif(isDevelopment, sourcemaps.write()),
      gulp.dest("public/css")
   ).on('error', notify.onError());
});