Disguard responsive theme less file not working?

hello team,

I have to create a custom theme. In a custom theme Theme.php,  I have added Following line to discard  responsive theme less file.:

protected $discardedJavascriptThemes = [\Shopware\Themes\Responsive\Theme::class];

clear cache and compile the theme properly working. So what is an actual problem, can not understand.

Please help to solve this issue.