TypeError: Object #<Gulp> has no method 'series'

[dasibre]

I get TypeError: Object # has no method 'series' when i trying running gulp with the example Gulpfile in the documentation.

I tracked down the error to line 56 in boilerplate-gulp-css/main.js:56:10
looked through gulp API and I couldn't find a #series method for gulp. Any help would be appreciated.
//_//
// Dependencies //
//_//
gulp.task('bpcss:build', gulp.parallel(
'bpcss:lint',
gulp.series(
'bpcss:clean',
'bpcss:bundle',
'bpcss:minify'
)
));